Oh, sorry to hear that. The game is really heavy on the system requirements. I've been playing on my (very) old PC and it is great until I reach the Soviet Installation or the Geothermal Valley (another big hub level), then the framerate drops to almost unplayable...
I'm actually waiting for newer Radeon drivers, too. The most recent seem to be "16.1 Hotfix", which I aleady have installed. I'm hoping that newer drivers will be more optimized for RotTR, but I fear that my poblems are more due to the old CPU I have...
Ah, well, at least I can play, even if it's just in a tiny window sometimes... I know it can be really frustrating if nothing works at all...