It is great that you have taken the mom into your garage. Some of the most important things to consider are 1) making sure the babies are tamed at an early age so they are more readily adoptable and 2) making sure the entire family gets neutered. In the meantime (as they are growing up) you should search for any and all no-kill rescue organizations that are near enough to you to help in placing the animals after weaning time. Congratulations on doing a wonderful thin for these cats.