I hope momma cat comes home soon. You must be worried sick about her.

In your house, you need to provide a place where the cat can run and not be near the dog if that is what she chooses. For us, we cut a hole in the bottom of the door leading to our basement. The cat can escape through it but it's too small for the dog. Many times I find the cat on the other side of the hole teasing the dog. In most cases, the novelty wears off and they learn to live in harmony. Again, I hope you find momma soon.