I would give her more time. You just got her today so I would give her a chance to settle into the house before introducing her to the dog. Give her at least a day by herself in a bedroom, then another few days to explore the house without the dog. Once she seems comfortable you can start introductions. Try leashing your dog to help her feel safe at first. Then introductions with a baby gate are also a good thing. Always make sure that she has her own place where she can escape to and feel safe and alone in case she gets scared. More than anything though I think time is the key.