Your CPU uses socket 939, which is kinda old. The best processor i could find that would fit in it would be a AMD Athlon 64 X2 4200+ Toledo for socket 939. Its a bit old and would probably be hard to find now. If you could manage to get one it is a dual 2.2 GHz processor, so it would greatly increase performance (in comparison to what you have now).
Edit*
That is actually a pretty good card, but because you have such a terrible processor you are bottlenecking like mad. I now recomend you just get a new motherboard and processor.
Ugh. I have no money. Parents Never buy me anything. Except for my birthday and Christmas. On Birthday, they spend around 50 bucks, and for Christmas, maybe a hundred.
How much for a good processor and board to match?
Plus I would need to buy new Ram due to the fact this is DDR.
And I think I would need new wires, right?
This is going to be ALOT more pricey than I had thought.
And power supply.
Oh god, I just bought a new one for this board, UGH.
Never going to happen in a million years.