How bout this: the baby's REAL mother discovers on TV that her baby, who had been kidnapped, was the one found in the tree. She never knew where it was, but when she found out the drummer to a big band found and eventually adopted the baby, she flies to meet him and possibly talk him into giving her baby back. Could lead to her and Bob getting married and forming a real family for the baby, or a big battle for Bob to give the baby back. It could go however you wanted cause of course, it's your story. :)
That's my suggestion. Kinda lame. But hey, I'm not writer so what do I know!! :D