Need Kitty Advice

Our neighbor/friend passed away in May and had two kitties that he treated like family. A neighbor offered to feed them after his death since they are cat lovers themselves. There was a family willing to adopt one of them, but it couldn't be caught and my DH was called to see if it would come to him. It did, but when he picked it up it scratched him so bad he had to let it go and after seeing that the family changed their mind. One evening "Little Girl" showed up on our front porch looking very thin. I didn't have any cat food, but she didn't mind eating puppy chow that night.

We asked the neighbor about it and they were told by the brother handling the estate not to feed them anymore. I guess they listened to him, and that is why she came to our porch. We bought some kitty food and left small amounts until we were sure that it was Little Girl eating the food and not possums or foxes. Little Girl now shows up at promptly at 6pm to be fed and Kenny's other kitty Taz has found out when the dinner bell is too. :o)

My dilemma is this: Both of these kitties were used to being inside at night. What will we do for their shelter when winter comes? DH has to take Benedryl even before touching one because of his allergies, and the dogs have never been around kitties before so coming inside the house isn't a feasable option. We don't have a garage, so we make to make some kind of shelter since it looks like they decided to adopt us. Any suggestions?