I don't mean this in a rude way, but why did your neighbour throw all the cats outside? Could she have partitioned part of the house so the cats had some indoors space, and her daughter and baby had a separate area? I don't really understand what's happened there, especially if you have some cold weather coming. The poor cats must be wondering what on earth happened.

Back to you, you'll feel bad if you do take in kitty as you're already at the end of your tether, but you'll also feel bad if you leave her to her own devices. So I think you should do what your gut feel is saying. Step back from the situation a little and see what your heart is telling you.

I would take her to the vet's for a checkup before anything so you can see if she's carrying any disease or if she's pregnant. That may influence your decision as well.

Good luck