The 8150 is not very good compared to other cpus in the price range without extreme overclocking.
If you are on a budget, the i3 2120 will do fine and not slow down your graphics card. If you want more processing power have a look at the i5 3570k (for overclocking) or the i5 3470 (no overclocking).
As for power supplyhttp://www.newegg.com/Product/Product.aspx?Item=N82E16817139020
The 6850 is a good card for the cost. However, if you have cash to spare have a look at current cards such as the 7770 or the 7850.