Definately new video card. When the new generation cards come out for ATi and nVidia you can get the cards that are now top of the line for a lot less than they are now. So wait a month or so to buy that. As far as ram, another stick of 256 or 512 if you can afford it. BF: Veitnam and UT2004 are pretty graphics intensive, so you'll need it.
And by the way, if you are going to be gaming, why not join up at TechIMO's sister site,
www.clanimo.com and play with us?