Need recommandations - Upgrade or buy new?

Hello everyone,

I bought this computer like 3-4 years ago already and built it myself (mainly for playing WOW). Now I'm done with WOW and I realize that new games are asking more and I have to run them on low graphic settings... which doesn't make an optimized gaming experience : )

My actual needs:
Playing games like SkyRim, Diablo 3, EVE online at an acceptable resolution/graphic settings without any considerable lag.


Actual Setup:

Windows7 (64Bit)
Board: ASUSTeK Computer INC. P5N-E SLI 1.XX (Bus Clock: 266 megahertz)
Intel Core(TM)2 Duo - 6600 2.4ghz (64 kb prim. mem cache, 4096 kb sec. mem cache)
4GB Ram (4x 1024 DIMM)
NVIDIA GeForce 8800 GTS
OS on 40 gig Raptor SATA-II
DATA on NVIDIA nForce SATA STRIPE

Now I'm wondering what are my options. I'm looking for the "best bang for the buck" option. Can I just (OPTION A) upgrade my video adapter and I should be ok or should I (OPTION B) consider buying a new whole setup ?

If option B is required, any recommandations ?

Thanks a lot for your time everyone,