P.P.P.S.: Another option you could try before opening your laptop (if you're crazy enough do open your laptop: i'd never do that) is trying to edit the ATI7000Controller.kext to inject your card: you copy the kext to the desktop, right click it and choose show package contents, open Info.plist with TextEdit.app and type in the string under the IOPCIPrimaryMatch the following: 0x99901002.
<string>0x99901002 0x26001002 0x22001002 0x67901002 0x67981002 0x679A1002 0x679E1002 0x67801002 0x68201002 0x68211002 0x68251002 0x68271002 0x682D1002 0x682F1002 0x68391002 0x683B1002 0x683D1002 0x683F1002 0x68001002 0x68061002 0x68081002 0x68181002</string>
Copy the AMDAccelerator.kext to the desktop and do the same, under AMDVerdeGraphicsAccelerator (which is incorrect for your card, it should be Thames or Lombok - unfortunately the plist doesn't have these options )
Put back both kexts in System/Library/Extensions.
Then you open DiskUtility.app and chose repair disk permissions. Cross fingers and reboot.
EDIT2: Can't I put both? so it Possibly recognizes both?
EDIT3: YES IT DOES HAVE LOMBOK!!
ANDDD on that string IT has the 0x94801002 already there