darkslash_323 :
Wow thanks for everyone's input. But I have another question regarding this. Is a quad core or dual core better for gaming? or it really doesn't matter. Because I kind of want this upgrade to help prolong his computer use a few more years.
Thanks.
It depends.
If your games are cpu bound and can make use of more than two cores, then a quad cores is in order. Most games today can not make use of more than two cores. FSX and supreme commander are among the exceptions. Most of the time, a duo clocked at 3.0 or better will be able to drive any single graphics card to it's capacity.
If you look at the following article and charts, you will see that a duo at 3.0(E8400) is able to give you good gameplay for most games, and that performance is primarily determined by the graphics card.
http://www.guru3d.com/article/vga-charts-december-2008/
Different games were tested the next year with a i7-965 @3.75, and you can see that performance similarly scales with the power of the graphics card.
http://www.guru3d.com/article/vga-charts-december-2009/3
Once you can consistently achieve 60FPS you will have good gaming. Do not bother much with the very high numbers. With a budget of $80, what can you do? I think I would do some looking on e-bay. Find out what your old card can sell for, and ust the proceeds to bid on a better replacement.
If, by any chance, the PC has less than 2gb of ram, use the $80 first to get it up to 2 or 3gb.