No CUDA and GPU option I have Blender 2.73a with AMD Radeon 3100 Graphics. I saw this page on how to make cycles render faster. It says when I go to User Preferences> System> Compute Device, It has no CUDA option, which means there is no GPU option. How can I fix this?
CUDA is only available for nvidia GPUs. AMD cards can use openCL (Disabled in official builds).

Here is the wiki page on it http://wiki.blender.org/index.php/Doc:2.6/Manual/Render/Cycles/GPU_Rendering