This is pretty much the best PCI card on the market. http://www.newegg.com/Product/Product.aspx?Item=N82E16814161074
It's really the only one that's going to play AOE3 at decent settings and it should play 2142 decently too. It's low-profile, so it's kind of annoying, but it's the best PCI card out there and for $100 it's quite expensive for the performance level it brings.
I wish I could give you more, but that's pretty much that. On the other hand, the rest of your system would probably bottleneck anything much better than this card, I'd say it's comparable to a 6600GT, which isn't the best, but it's sure better than the next step down 6200 or even worse the dreaded FX 5200.