Before making your OpenGL and Quartz acceleration work, update your OSX to at least 10.5.3. Since 10.5.1, there have been hundreds of improvements, also in graphic card drivers. I'm not an AMD user, so you'll have to search for a proper way
of making update on your own. Maybe you should try Zephyroth AMD Updater.
Search old posts on this forum and insanelymac.com.

When you'll finally get to 10.5.3 or something above it, download NVKush Installator from http://diabolik1605.com/DHF/
Before running it, remove nvinject!
NvKush is a lot better at dettecting hardware properly, than nvinject. It works properly on the more recent versions of 10.5 too.

Regards