How do you enduce labor in a cat?

It's winter and I know that my female cat is pregnant, she lives out in the garage and kittens have to be at seventy degrees or more so they would die if she had them out there. My dad won't let her live inside til she actually has them. I know that she is going to have them soon so I want to have her have them inside during the day so that she can have a reason to stay in.