Depending on how much money your wanting to spend, this card will allow you to play TF2 very smoothly at that resolution if you don't mind spending a extra $20.http://www.newegg.com/Product/Product.aspx?Item=N82E16814125281
^+1 i think that's the latest video card out on agp if im not mistaken (featured on either this site or on anandtech)
and it's $5 cheaper than the ati 2600 or the 3850..
that specific video card's psu requirements is 400w minimum..
it says the video card supports crossfire but it doesnt have the crossfire bridge connections on the card, and ur mobo prolly doesn't support crossfire since it's as old as agp with no pcie..
this is the best ur gonna get! (get a psu from a quality manufacturer such as corsair, pc p&c, etc.)