It is possible to hook up 3 monitors using one video card but you need one of these or similar.
a bit of a rip off, but is convenient. I dont have one, Im only using 2 monitors. There's a more expensive digital version too. I dont know what the diff is or much about about them at all.
http://www.i-tech.com.au/Library/Include/PrintItem.aspx?id=12025&name=Matrox%20TripleHead2Go%20Triple%20Analog%20Edition
