If that's a GeForce 3 Titanium 200 that you have, yes you would see a difference going to a better video card.
As for the amount of ram, changing that alone won't make a massive difference. I'd say if you are running Windows 2000/XP you might want to consider going up to 512 MB, but don't expect miracles. If this is Windows 98/ME you won't get much of a performance boost at all by going to 512 MB.
Personally, I'd wait and see what your framerate is with future betas. I'm sure there is plenty of debugging code to be removed and optimizations that can be made to AH2 before it goes final.