I'd really say slap another 512MB in there. If not 768MB. It's pricey though so you might not want to. Like I said, ask someone that knows more about computers, i'm just an amateur. Your video card would be fine but i'm not really up on the Geforce cards, i'm more of an ATI guy.
Did your computer run the game before? If so, did you change anything since it last ran?
Good luck