The first thing I would do is overclock the video card.
The card you have overclocks really easily:
CLICK HERE for Cool Bits instructions
I was able to get mine up to: Clock - 500MHz and Memory - 515MHz without any problems. Probably could've gone higher on the clock speed, but the slider maxed out. The memory was tricky though, it got unstable over 520MHz.
I have had mine clocked at the above settings for several months without a problem.
That's a free little upgrade that only costs you a little time.
Next:
What is the brand/model of your Motherboard? You might be able to spend a few bucks, get a little better processor, a little better memory and be on your way without spending a lot of cash.
If you have the cash, I would also look at a bigger/faster hard drive....
and.....
Get rid of IE and use
FireFox