7 x64 with x32 Graphics?

i have the x64 based system, but im my resolution settings, it says that i am gisplaying in x32 bit, so whats the problem with it?

AMD Radeon sapphire hd 6570 with amd cristal catalyst

You have no problem 32 bit color is the highest setting.
Has nothing to do with your system being a 64bit os.

Correct.

Your OS is 64-bit - making full use of the internal CPU execution and memory access structure, which determine Windows' ability to run 64-bit code and access more than 4GB of memory.

Your videocard is displaying your desktop with a 32-bit depth per pixel, which is 24 bits of color information (16.7 million colors) plus 8 bits of alpha blending/transparency (which Windows Aero uses for its transparency and blending effects, among other things).

It also has nothing to do with resolution. It's the bit depth per pixel, defining how many possible colors each pixel can assume.