do yourself a favor (if possible), get the safe out of the garage. Garages, cellars, and attics are bad places for safes in my opinion. Depending on the home, some basements can be ok (mine isn't one of them / moisture is an issue and there can be other issues). Your fighting a losing battle if the atmosphere where the safe is can have moodswings and/or isn't good. Where you live mostly that you keep cool enough or warm enough for yourself to be comfortable throughout the seasons is the best way to go. It is also closer to you and harder for a BG to access without you knowing.
I want to move the safe to my family/computer room, but my wife wants to leave it out in the garage of at all possible.
definately work on her about this. you are in the right in my opinion. explain it will cost more overtime otherwise and possibly much more. its a lifetime safe probably - take care if it(not saying you don't - just sympathizing with your dilemma). it will end up being too much of a headache that can be avoided.