1GB of RAM will definitely help, but right now his largest crippling hardware is that archaeic video card. Even going up to an FX5600 (a crappy card by all rights) he will gain an immense boost in performance.
Adding to what Roscoroo said,
Ignore all 6000 cards before 6600, all 7000 cards before 7600, all 8000 cards before 8600, and you should be okay.
For ATI fans, go 9600, X800/850, X1600/1650, X1950 and nothing in between. Note that an X1550 is not close to an X1600 in performance. Quite annoying how they do that.