How about if I replace the Power Supply with this,
CORSAIR CMPSU-850TX 850W ATX12V 2.2 / EPS12V 2.91 SLI Ready CrossFire Ready Active PFC Power Supply - Retail
and the Video Card with this,
XFX GX260NADFF GeForce GTX 260 Core 216 896MB 448-bit GDDR3 PCI Express 2.0 x16 HDCP Ready SLI...