Cpu or gpu upgrade ??

Hello Guyz,
I need sum advice,
I hav around 200$ & i really really want to improve the performance of playing games.
yesterday i installed crysis just to play the beautiful game again. The settings were set on
high with no AA on 1680x1050 res & i was getting 28 avg FPS.
I was really freaked out cuz i couldnt play with all of those laggings. So rite now i dont know what to upgrade either my GPU or my CPU?
I was thinking to get AMD Phenom II 940 for CPU & ATI 4850 for crossfiring.
My specs are;
AMD Athlon X2 6000+ @ 3.2ghz
MSI K9A2 Platinum Mobo
HIS tech ATI 4850 512mb
Corsair 2gb 800bus ddr2
viewsonic VA2226w LCD
WD 80gb HDD

( dont mind the HDD cuz ill be changing tht too with WD Caviar black 500gb 32mb cache )

So guyz plz help me out & tell me wat to upgrade for the best performance.
& when im gonna upgrade any of those i hope ill get atleast 38+ FPS in crysis HIGH