Need advice for new graphic card



which one is better, hd 3870 or 9800 gt. i want to buy one of them next month. i have e7400 2,8 ghz
asus p5kpl cm
ddr2 corsair 2x 2 gb
pixelview 8600 gt 256mb
simbadda sim-x casing, included PSU.

which one is the bottleneck? To what should i upgrade it? i want to play pcsx2 emulator, and gta 4 (pc)with enjoyable fps
Danke! your help is much appreciated
the new gpu probably won't help a whole ton with pcsx2, for that you need a very good cpu
ie 3.4-4.0GHz, dual core is fine since it only uses 2 threads

GTA4 we recommend a quad core at the minimum, the game is very cpu and thread heavy (bad console port)