I'm rather surprised actually of how high that score is for the spec of the computer you have
I mean, that video card isn't exactly high spec, and niether is the processor, though that 6600GT will perform alot better, and that score should shoot up quite considerably. Good luck with it!
Remember, 05 is th latest test for your video cards, and even high specced machines dont get that much of a score. So, it is to test how your comptuer would cope with games in the next year or so.
For your card, you should be running 03, and will get a much higher mark for the type of games it was built for.
When you get the 6600GT tommorow though, you should see a big improvement, trust me