Mike...
Welcome to the forum. You will get all the advice that you need to help those new trees to survive. The unheated garage is good.
Forum members....Can Mike throw the 1 gallon pots into larger, soil-filled, 5 gallon containers, to create a buffer zone for the root area? Over-winter the trees in the unheated garage. Then when Spring-2013 rolls around he can just slip the plants out of the 1 gallon pots and plant them into the 5 gallon pots? I doubt this will disturb the roots, and, the plants will then be up-potted.
Just a thought.
Frank