If you were in a bind for $$ then I'd say put in a replacement alt. But if you have the cash and a few extra minutes....buy an SN95 alt. intended for a '94-'95 5.0L Mustang they are 130amp and rewire it, there are many sources of info on how to do it.
Minor problems can be very frustrating if you don't know how to fix them, but once you've done it once, that is valuable information that you can take with you through life.....doing repairs gets insanely easier as you go on and one day you'll look back and laugh at yourself for wanting to ditch this car because of the problems you've had!
Good luck!
www.mralternator.com/mustang-130amp.html
www.racesystems.com/3gproj/index.htm