Well, I did upgrade this thing, just didn't finish my goal. Here is the information about my pc right now:
CPU: Intel Core 2 Quad Q6600 x86 2.4Ghz (original)
Graphic Card: nVidia GeForce 9800 GT EVGA (new)
RAM: 4 GB DDR2 (new)
CPU Fan/Heat Sink: CoolerMaster Geminll S (new)
and I bought a new case fan from Fry's just to have better coolings.
That's basicily it, my video card is such a monster, and 4 gb of ram can help me with the rendering speed. Overall it cost about 250 dollars which is not bad. I'm pretty satisfied with the performance than before.