Woh, he bought a 150$ card and he cant use it..
I dont think theres much hope. Any motherboard with AGP has a socket 478 CPU, wich is what he has. And he wont find a motherboard with PCI-E and socket 478.
Best chances are to go back to the store and tell them to give u THE SAME card for AGP, they probably will since the card dosent actually fit ur motherboard.