I think using Acronis products would help you a lot in this case.
Check out the following excerpts from their site. Basically you would have a central server with their Management Console app, from which you would manage backup and restore activities. Then, each of your 30 workstations would have the Windows Agent component, which would allow them to be backed up remotely.
You could either copy the backup files to a USB hard drive (handy and portable, and you could have multiple drives to swap out and easily take offsite in case bad weather is coming, or some other case where you need to evacuate), or you could have the files be written to the server from which the Management Console runs, and have that machine be the one to burn them to DVD-R.
One note about your current system with the DVD writer, the CPU speed is fine but you need a LOT more memory to write DVDs without errors! Try a minimum of 512 MB, ideally 1 GB or more. You may also want to upgrade it to Windows XP.
I’ve used Acronis products before and so far have not had any bad experiences with them. I’d strongly suggest exploring these options:
“Acronis Management Console
The Acronis Management Console provides remote administration, ensuring that all systems in your network, regardless of your domain and workgroup structure, can be accessed and managed from one location.
How does the Acronis Management Console Work?
Step 1: Install the Acronis Management Console on any machine in your network.
It is important to note that the Management Console can be installed on as many machines as you need. For example, if you have three administrators responsible for managing your backups, you can install the Management Console on the three systems used by these administrators. Moreover, this component can be used to manage both servers and workstations running Acronis True Image.
Step 2: Open the Management Console and install the Acronis True Image Agents on remote systems in your network.
Step 3: Begin managing systems, scheduling backups, and recovering remote systems in your network.”
(from http://www.acronis.com/enterprise/produc…
“Acronis True Image Windows Agent
The Acronis True Image Windows Agent is a component of Acronis True Image that allows you to remotely manage backup and restoration tasks on Windows systems in your network.
How does the Acronis True Image Windows Agent work?
Step 1: Open the Acronis True Image Management Console and select to install Acronis components to a remote computer
Step 2: Select the Acronis True Image Agent and the remote computer where you want to install the Agent
Step 3: Install the agent on the remote machine
Once the Agent is installed, you can manage backup and restoration of this system from the Acronis Management Console. The agent performs all of the tasks on the remote system.”
(from http://www.acronis.com/enterprise/produc…

Genie Backup Manager Pro v8.0.364.534
Windows 2000/XP/Vista/Windows 7 (All 32/64 Bit)

Genie Backup Manager Pro is the backup solution for Small and Medium Business Users that easily want to back up and recover their entire system.

Never suffer from data loss by computer viruses, equipment failure and security breaches.
Backup your files and folders to a secure location and recover your data in an instant or perform a complete backup of your system (Disaster Recovery) to recover from failure.



Migration from Windows XP or Vista to Windows 7:

1. Select Backup> create a job and select your data from My Profile, My Folders, and My Plugins to any location, Local/LAN, removable media, CD/DVD, and even remote locations like FTP and Genie Online

2. Install Windows 7 and your programs.

3. Restore your backup.

Total system and data protection solution that combines ease-of-use and robust performance.
It allows users to perform fast backup and recovery jobs reliably, and protects all MS Windows based desktops, laptops, and networked systems against various types of threats such as system failure, human error, and disaster.

Windows 7 compatible disaster recovery feature, guarantees your business continuity by backing up your whole system (Operating System, Applications, Documents, E-mails, Settings, Desktop, Files/Folders, MS Outlook, and Win Mail, etc) and offering faster and easier recovery without the need for MS Windows installation CD, through a clear cut wizard-based interface.

Backup their data to virtually any storage destination including: Local/LAN location, Removable Media Devices (USB, REV disks, Floppy disks, etc), Remote location using FTP, CD/DVD media, Tape Drives, as well as Online using Ajax-based backup technology, offering better data management and greater data availability.

Higher reliability as it packs everything under one roof by providing a built-in open/used files backup agent together with an easy-to-use smart backup scheduler where users can set GBM to perform different backup jobs in different times and intervals, snooze or even pause scheduled backup(s), and prompt GBM to postpone backup if the system is running on batteries (Laptop Power Optimization Support).

Using U.S. government-certified Advanced Encryption Standard (AES), Genie Backup Manager Pro V8.0 provides premium security and prevents unauthorized access to backed up data, and employs a 128-Bit Secure Socket Layer (SSL) for data transmission, certified by the leading global provider of SSL certificates Thawte, assuring data integrity and forbidding eavesdroppers from intervening data.



Features:

• Backup your entire PC
Genie Backup Manager Pro includes the option to backup your entire system so you can restore in case of failure

• Safe Remote Backups
Safeguard your data from natural disasters and system failures to secure offsite storage location

• Backup locked & open files
Ensure business continuity without the need to close data or applications during backup

• Protect your business asset
Encrypt your data using U.S. government-certified Advanced Encryption Standard (AES: 128, 192, 256-bit) encryption security

• Iomega REV Support
Backup to virtually any storage device including the famous Iomega® REV Drive

• Continuous Data Protection
Set backups to run automatically at preset time intervals and rotate different backup types.

New Pro v8.0:

* Disaster Recovery
GBM can recover your system from malicious spyware, virus attacks, system failure, or deletion with the enhanced PE technology that also supports Vista and you can perform yourDisaster Recovery backups online

* Free Open File Backup Option
GBM currently added Microsoft's latest Volume Shadow-Copy Service (VSS) framework, to permit consistent backup of open files without the need for additional applications or plug-ins.

* Enhanced Online Backup Integration
Now it is easier to view, manage and delete your online backup storage.
Added Bandwidth Throttling to control how much GBM takes from internet connection.
Also improved connectivity that auto resumes when connection returns.

* Improved Scheduling Capabilities
Now it is easier to protect and rotate backups with the intuitive easy to use scheduling interface that is integrated in the backup wizard with two modes; Basic Schedule and Advanced Schedule

* REV Support
Now with the new Iomega REV support, users can automatically erase, enable/disable write and password protection before and after backup.

* Enhanced Graphical User Interface
Now more organized with clear options making GBM’s interface better than ever

* Enhanced Filtering Options
Added support of Date and file size filtering and newly added in scripting

* Control Power Options and Backup Speed
You can control backup speed before or during backup and enable/disable power options or change them during backup.

* Pause/Snooze Backups
You can pause currently pause backups and postpone scheduled backups to start later via snoozing

* New Compression Engine
The new zip engine is more resource friendly making backups faster and with better compressing capabilities

* Improved Connectivity
GBM now detects when backup destination is accessible and also reports disconnected network drives being backed up