OH I am so happy for you. I'm in tears reading that.
When I had my first ultrasound I lost my wedding ring (nothing NEARLY as eventful as your discovery :) ) and I looked everywhere for it and I called the clinic to see if they had found it. They called me back a little while later to say they had found my ring in a wad of paper towel in the bathroom of the room I had my U/S I was so grateful
We sent them flowers.
Perhaps a nice thank you card or something for them would be nice :) they really do show miracles dont they :)