[H] AGP video upgrade

[Winterlight]

I am doing a new build on a old box. This PC uses a ATI All in Wonder 
X800 which has been problematic for my setup. And since Paypal/Newegg 
is having a 20 percent off sale, I am thinking of getting rid of it, 
and getting a Nvidia AGP, with a Haupagee dual tuner PCI video card.

What is the fastest Nivida AGP... a GeForce 7900GS? Will this drive a 
30 inch monitor at 2560 x 1600?
thanks