update CPU or motherboard, RAM and CPU

Hi! I have a question. My pc have a phenom 9950 x4 be, 8 Gb of ram DDR2 800Ghz, motherboard is m4n82 deluxe, and not long ago i bot an xfx r9 270x. Right now i have a big bottleneck(when cpu is at 100%, the GPU is at 50%). my motherboard supports the phenom II x6 like 1055T (90€ ebay) or 1100T(150€ on ebay) that will reduce the bottleneck. my question: In it worth updating only the CPU keeping in mined that i have ddr2? if it does, witch one of Phenom II x6 should I buy? if not, say so please! Update CPU or update Cpu, ram and motherboard.

I think update cpu, mb and ram is the best choice. That cpu and ram are too old. Is not worth to spend money in that obsolete socket. Tell us how much money can you invest on it, in order to be able to advise you properly.

Sorry for my english

PS. You could try overclock too.