Time to make Gameplay faster!

[Danny]

I was purely stating that you don't need a quad core processor to run GTA IV with good fps. What you do need is RAM. I noticed a huge amount of difference in frames when 2GB of ram was taken out of a computer with 4GB originally. Especially on Windows 7.

For your $200 budget I'd personally recommend buying the following hardware:
ATI Radeon 5670 1GB
AMD Athlon II X2 3.2GHz
G.SKILL 4GB DDR3

Total: $190

With shipping, should come up to around your maximum.

This should Run GTA4 around the same as (probably better than) this guy's computer: (bear in mind he's recording with fraps, which drops the FPS by about 15-25)

Gta IV - XFX Radeon HD 5670 1GB