Name that slot...

[ffutures]

My brother-in-law gave me a copy of Doom 3 for Xmas, but it doesn't want to work, presumably because my PC uses the motherboard graphics which don't have hardware acceleration etc. I'd rather like to play it, but I'm not 100% sure what graphics cards will be suitable for this machine. It has two empty PCI slots, plus another (the brown one circled in this picture) which I think is AGP. Can anyone verify this, and make any suggestions as to a suitable (and preferably cheap) card?