You can't have GPU acceleration for ray-traced 3D compositions with an ATI card, you're only option is to render with CPUs (quite a bit slower to process). GPU acceleration for ray-tracing is only for specific NVIDIA GPUs.
Also, check out this blog post: http://blogs.adobe.com/toddkopriva/2012/05/gpu-cuda-opengl-features-in-after-effects-cs6.h tml
Hey Kevin thanks for answering my question so quickly! I noticed in the new update for After Effects their was an update for nvidia. Will After Effects get updates for ATI so it can be used with gpu acceleration?
Sorry, I can't really comment on any features for upcoming versions of After Effects. It may be worth noting that Premiere Pro CS6 now works with GPU acceleration on ATI cards, so you never know. I recommend submitting a feature request: http://www.adobe.com/go/wish
okay cool, I actually just did that! Thanks