That's some bad luck! It's always worked great on my 5870. Looks different from the screens of if you have AA enabled in your CCC (which causes errors with TW2 so don't do that), but I'm guessing you tried setting all the AF/AA/Adaptive AA to application controlled and/or off? AF really should work forced to 16xAF though, leave that at 16x if you can.
I see it being suggested you might have the MipMap detail setting to Performance instead of Quality (should be always on Quality), if you can't find it, you may have to search for how to edit it manually, it may be hidden, or download the RadeonPro and see if that lets you fix it (it's like nhancer for ATI cards).
Also make sure you don't put Texture Downscaling to high in the Witcher 2 config tool... that one you want off or the equivalent as you don't want the textures downscaled.
Other than that, I don't have much else! Hope you get it straightened out.