I'm sure you can find a female who will work. To be on the safe side though, I'd try to choose one who is pretty submissive. I'm sure the foster moms have several other dogs in their households so you can find out how she is with other females.

Whatever happens, there may be a rocky start to it. But don't worry, I'm sure you'll be able to work it out so that you, Samantha, and the new dog are all happy!