Yes they have a couple of slots. It was just interesting the demo computer didn't allocate system memory to video, and when the 99 other PCs arrived they did just that.
Something cheap like this... look at the customer reviews... one guys says he gets a 5.4-5.9 in Vista 3D with it..
Not to shabby, for reference my OnBoard Geforce 6150 gets an even 3.0 ;)
And remember not only is the dedicated video card faster for 3d graphics, but also gives you back your system memory... ;)
they have Tons of cards over there at newegg.com you just really have to get what you need for the price you want to spend... I just grabbed one..