Sorry Dom! Sounds like a tough situation. I guess, like you mentioned, the best thing to do would be to try and feed the heck out of her and release her. As a matter of fact, bat's are pretty good navigators and she may be able to find her way by herself to whichever cave or hibernacula she was using.
The Herp Room
"The day I tried to live, I wallowed in the blood and mud with all the other pigs" - C. Cornell