If it was me, I would go to another groomer. Something is very suspicious about their behavior after being groomed there. Of course, I'm very protective and when I even think I see a warning sign, I follow my "mother's instinct." I would be afraid to take mine back there. Something happened.
I have these bells hanging at my doors. That's how I taught mine to ask to go outside:
http://www.poochie-pets.net/
Of course, you could just make your own. Perhaps she isn't too old to learn something new like that. I just took her paws in my hands and reached up and rang the bells. She caught on very fast. There's a video at that site and you can see how it works. Good luck.
When I was house training mine I used Simple Solution from Petsmart to clean up the accidents.