Help building a pc!

Hey forum,I was planning on building a pc for about 500$ (with windows 8 os) but Idk which CPU to choose to build around. What I want in my pc is a motherboard which supports PCIe 2.0 (sli would also be appreciated but not 100% needed) and a CPU that can support Asus GeForce 650 to boost 2gb without bottlenecking it. What I already have is a 600 watt PSU and a disk drive. What i plan on doing is 90% gaming. Please someone help. any advice is appreciated. 


unless you already have that card or are getting an amazing deal you may be able to better, also you dont need a $60 cooler, figured why not go to your limit

Does that motherboard have two PCIe slots?also, why does everyone recommend the AMD-fx 6300 and 6350? Is it much betterthan an I3?