Graphics acceleration on an HD 7770?

Hello! I finally got my hackintosh to boot, but I'm having issues with graphics acceleration - it doesn't work at all.
My specs:
i5 3570k
Asus P8H61-L R2.0
12 GB DDR3
Asus Radeon HD 7770 2GB Edition

My SMBIOS is set to iMac 13,2 - if that's any help
Any help is appreciated - thanks in advance!