New videocard for my PC

So my PC specs:

- E8400 processor(stock 3.00 Ghz).
- Intel classic Motherboard(Doesnt allow overclock plus i never done OC).
- 4gb ram DDR2 Kingston 800Mhz(on cpu-z shows 400Mhz but that means supposedly to be 800Mhz).
- 260 gtx core 216.
- Vigor Monsoon III LT HS(keeps processor between 37° and 45°(stock HS was between 45° and 75°).
- HAf 932 case.
- 320 gb Hard Drive.

The game i play most of the time is cod4, but thats a 3 year old game i think, and i get between 100 and 300 fps, and if i look to the sky or corner myself i get a max of 700 fps, meaning its 100% playable, but im moving to bad company 2, plus i upgrade from 22" 1680 x 1050 to 32" 1900 x 1200 and on Bad Company 2 on 1900 x 1200 with all graphics at low i get around 30 fps. So i was thinking about getting a 5850... is that a good choice? Because i have been reading that E8400 is the best dual core processor that Intel has and wont bottleneck the videocard.