the reason it is where it is is this, its the start of the circuit, and any outlets after it are protected.
you CAN move it into the bathroom BUT place it at the first one on the circuit line in the bathroom. thatway any following ones in the bathroom are protected. and just move the standard outlet out to the garage. should a electrician do it? hmm.. they have to follow building codes'n'laws. so most likley they wont do it.
once you have switched the 2 outlets when it blows only the ones after the GFCI will die, but the ones before it will still work. (it just breaks contact with the line wire coming into the outlet to kill power).
--edit--
Editted to say.... TURN OFF THE BREAKER FIRST! never work on a live powerline unless you know what your doing.
now to find the first outlet in that line that is in a bathroom will take some work. which bathroom is closest to the garage? generally it will be that one. now.. turn off the breaker and open one outlet, pull it from the box. disconnect one set of wires. (one white/black pair, ignore the bare ground) ensure that the outlet and the disconnected wires will NOT be touching nor will the disconnected wires themselves be touching. plug somthing into each outlet in that bathroom. turn them on. go turn the breaker back on. one or none should be on. if none. if one is on. you found it. if none, you found it.
the reason both ring true is this
One : you have power coming to the outlet bot not leaving it, you pulled the wires going ot the next.
None : You pulled the power lines bringing power into it.
now there is a chance that the one you have pulled out can be the second one, this will be evident by the pulled one having no power to run whats attached and the one still mounted does have power.
now if both are equal distance you may have to check the other one. hiring a electrician to track the circuit may be best if you dont feel confident in messing with 120V powerlines. trust me getting shocked is NOT fun. doublt so if you get hooked on it. remember loony toons? the flashign skeleton? pretty close...