video card compatability

i have an asus p5n32 e sli motherboard, currently have a nvidia 8800 gt video card, me need to upgrade, i need to know what video cards my mobo can support, cause now they have pci express 2.0 16, i know mine is just pci express x16 ddr2. so can a get a pci express x16 2.0 ddr3 in my mother board to work