1.) 6 cores is unnecessary for gaming,
2.) 5670 is a very underpowered card for your range
3.) i7 950 is old tech, sandy bridge is the way to go now.
All in all if you want to build yourself there are great how to's all over. there are 3 videos on this page, as well as a plethora of how to's if you google it.http://www.newegg.com/Store/Computer.aspx?name=Computer-Hardware
My recommendation for you is. i5 2500k. Radeon 6950 1GB. corsair 750W psu. and everything else is up to your preference i guess.
If you are looking for a place to buy, I heard CustomPCandRepairs.com is really good if you call them or email them or something