I don't have a garage so I'm in the same boat as you. I usually go to a coin op up the street during night time or early early morning, wash their and apply wax. Or my friend finds a underused underground parking garage and does his business there, he obviously pre rinses elsewhere first.
Or if your not willing to do any of those contact Big A(He's here also find him on google Big A detailing), let him detail it for you now and then do it for your self once the warmer weather comes in.
I infact go to a production detailing center only because they use 2 buckets, wool mitts and it's only $10. But's only during -10 or more Degrees C.