that PC is not built for gaming.
a $40USD video card is nearly 4times better for gaming.
While it's spec's are impressive, it's a workstation PC, most of those attributes are not overly beneficial for gaming.
I have almost the same setup just different video card - GF8600. Your card isn't for gaming that's for sure but I think there is some combination in settings that will allow you to play smoothly :) I would check forums for your Video Card FAQ or something :)
rofl @using CAD computer for CS