Upgrade time! please help me

hello everyone,

about 4-5 years ago i build my own desktop with a neighbour who knew exactly what hardware to pick. I, on the other hand, did not and do not know very much of hardware. But I've come to a time that I want to upgrade my pc, since i cant run some games (like BF3) at max grafics anymore... and we cant have that ofcourse, now can we ;).

so here are my specs:

MB: Asus P5KPL-C
PSU: Corsair tx750w
CPU: Intel Quad core Q9450 @ 2.66 GHz
GPU: Nvidia GeForce 8800GT
RAM: Corsair VS2GB800D2 + Corsair VS2GB667D2

so again, my pc is working fine, its just getting outdated. so id like to upgrade it, so it can run all games perfectly again. like battlefield 3 and the upcoming battlefield 4 at max grafics (i hope this can be achieved with my current MB).

i think i will need to upgrade my RAM and my GPU. i searched a bit on the internet and im coming to like a Radeon 7750 or 7770 is the max my i can do with this mb. but please prove me wrong because id like a better one ofcourse ;).

please leave my your opinnions what i should do with my pc.

greetings,

ivek1991