Hi In. From my research i see that the card is a PCI-Express card and therefore you can pick up a few of the more modern graphics cards online, as i suggested in a earlier forum try looking out for the GT 2 series start at the GT210 as i know you can get these guys in small form factor also look out for Nvidia GT430 there newer range of products.
Wrong on most points.
The 5670 totally KILLS the G210, really everything does
It also slaughters teh G220 and beats the g240 by a respectable margin.
The GT 430 is the worst price/perf card ever created by mankind. (Just saying)
You can look into the 5570, 5670, or the GT 240.
Anything else will cuase a bottleneck. Any Radeon 5 series gives DirectX11 and any Nvidia 4xx or 5xx series also gives DirectX11