That doesn't appear to be the model number--it's probably some other number that was printed on the motherboard. If you load up Belarc Advisor, it should be able to tell you the model.
There are plenty of DDR RAM available on newegg.com / newegg.ca, though the running price appears to be about $70 CAN for 2x1GB. You can't get DDR sticks any larger than 1GB. I can't give you a specific set of RAM without knowing what the motherboard can handle.
As a general rule for an older PC, I wouldn't spend more than $150 for upgrades or replacement parts.