Graphic Design is a pretty standard major these days. If you've already got a bachelor's degree, though, I'm not sure if it's offered at the graduate level. You probably have to do something very 'specialized' to do Graphic Design at the masters level. Getting another bachelor's probably doesn't hurt, though.
You might be able to do this online without even having to move, or even drive to classes. 'Distance Learning' is booming, especially in computer-related fields. Many degrees can be obtained with minimal 'sitting in the classroom' now.