You have a pcie 1.0 slot. All of the new cards are backwards compatible though. Depending on your system specs, many of the cards sold today will be bottle necked by the rest of the system. What do you intend to do with it and what are the specs of your PC?
Thanks for the help I selected a PNY - GeForce GT 610 1GB DDR3 PCI Express 2.0 Graphics Card from Best Buy for $44.00, install was a breeze and it works great.