PC Upgrade Help

Guys I am looking to upgrade my PC to play the likes of BF3 and other games. I'm thinking about purchasing the Msi Radeon HD 7870 and getting a better PSU as I am pretty sure that my current one will not support it, but I'm concerned that my CPU will bottleneck the GPU. I was considering getting a new motherboard and getting the AMD FX6300 6 Core @ 3.5GHz along with 8GB DDR3 --- But I will only do this if I need to.

Your help is much appreciated :)

Current PC:
Intel Core 2 Quad Q6600 @ 2.4GHz
3GB DDR2 667MHz
Nvidia GeForce 8800GT
approx 350W PSU
Windows 7 32-bit

i would send u a link but im on my tablet and i cant send links on it. 

CPU-AMD phenom ii x4 965 BE                    CPU cooler- coolermaster hyper 212 evo   Graphics Card-HD 7870                PSU- corsair CX600              Mobo- Gigabyte 990fx-ud3               Case-NZXT Phantom 410             RAM-Corsair vengence 8GB 1600MHz RAM       Storage-500GB western digital caviar black hdd            Use the parts i listed as a rough base for ur new build