Was she born after you became PR? If yes, you can only sponsor her for PR after at least one of the parent actually moves to Canada. As a USC she can travel to Canada with you, but she cannot stay there beyond 6 months (You will have to separately apply for extension of stay beyond 6 months). The PR sponsorship application can take 6 to 12 months. She will not receive provincial health coverage until she actually becomes PR.
If she was born before you landed as PRs. She should have been included in your PR application. You will not be able to sponsor her for PR ever in that case.