Is this DDR or SDRAM? If its ddr what speed is it? I would suggest(if its DDR, and less then 400) upgrading to DDR400(That is if its suported)and 1GIG of it, you can do this with less then 100$'s easy, and then there is 100$'s(prabally much more) for a video card. Not sure what i would sugest getting because im not up to date with the differernt video cards.
but you should be able to make it play new games with 200$'s of upgradeing, and that is the only two things you should have to upgrade...