@ AOD - I have a 6600 GT and I'm really quite surprised at its performance. I bought mine about a year ago and it still runs well. I can easily play Half-Life 2 at full detail settings (no AA or AF though) with a pretty good framerate (about 45 FPS).
The RAM is definitely what's holding you back. Make sure your motherboard will support DDR400 RAM (I'm pretty sure that it will) and get some. Get at least one gigabyte of it and you'll see a huge improvement.
The RAM is definitely what's holding you back. Make sure your motherboard will support DDR400 RAM (I'm pretty sure that it will) and get some. Get at least one gigabyte of it and you'll see a huge improvement.