Where there is one male tom-cat there will be more. Buy yourself cat/animal trap, put half a can of sheap cat food in it near wherever the possible entry is to the garage and you'll have a cat within 2 nights. The more difficult part is finding a cat rescue organization that will take it, s they generally only want ones that are <1yr old. If you have an animal control department in your city/county, then they may take it.