I want to agree with julie, you are talking about the possibility of having babies even as early as tomorrow, I believe. Mine whelped on day 59 from first tie. I would be on stand-by for the next 7 days - do not leave her alone, make her a box. You don't want to take a chance on something happening to YOUR baby. That was my biggest fear with Zowie. Everything was fine and she has done a wonderful job being a mommy, but that is not always the case.
I wouldn't worry about the stud fee right now. If you have one or two puppies and they make it 12 weeks - you have plenty of time to discuss that with her, and us
Good luck and keep up posted.