Your computer (specifically the processor) is very, very slow for Super Mario Galaxy 2. Here's the best settings I can give you.
If your NVIDIA graphics card is very new (GTX 6 or 7 series) use Latest Master and OpenGL. If on an older NVIDIA card, use a build before 4.0-722 and make sure to check the Vertex Streaming Hack in OpenGL's Graphics Settings/Hacks. Check Skip EFB Access to CPU except when you need to use pull stars. If it's still laggy, you can try the frameskip option, but at that point we're grasping for straws.
If your NVIDIA graphics card is very new (GTX 6 or 7 series) use Latest Master and OpenGL. If on an older NVIDIA card, use a build before 4.0-722 and make sure to check the Vertex Streaming Hack in OpenGL's Graphics Settings/Hacks. Check Skip EFB Access to CPU except when you need to use pull stars. If it's still laggy, you can try the frameskip option, but at that point we're grasping for straws.