Yea, 7600GT should be around 3000-5000. I bought one sometime ago when it was going for 14,000. What a sap I was.
It's powerful enough to play CoD 2 and and other games @ full but it's not really high-end.
But it's not really worth it to get a AGP card right now, they are obsolete. Your best bet is to sell your machine and buy a new one with a PCI-X slot and a dual core.