You have a perfect job for your career path and cheap graduate education (and you're clearly an important asset if you are being promoted). By staying, your worst-case scenario is to stay in the same situation you are now. By moving, your worst-case scenario is to graduate with greater debt and no prospects. And remember, not only will the program cost money, but your cost-of-living will increase.
Economically, it does not make sense to move. If you can tolerate this area for a few more years, you will gain valuable experience and a graduate degree, be able to pay down your debt, and invest for your future. Your work experience, in the end, will be extremely valuable -- perhaps more so than your degree, unless you are attending a world-class program.