Sounds to me like she's basically made her decision....she's done and moving back to Germany. The only thing left for her to do is say goodbye to the kids and get the paperwork finalized. Obviously you should have clarified her purpose behind coming before you told the kids.

Since she's all business with this trip, I'd suggest that you NOT roll out the red carpet. I might even go so far as to ask, "where are you staying?" Seriously, ask where she is staying. If she said she intended to stay with you, then either say, "I guess you could crash on the coach or maybe one of the kids will give up their room" (unless you have a spare bedroom. I would not let her assume she has a place to stay with you. She needs to see you strong and confident. She needs to see that you are fully capable of moving forward with your life. She can't see someone that is needy, desperate, and like a puppy waiting to be pet. You've got two weeks to put some doubt in her mind...it won't be by kissing her butt. Show her a person that resolved his issues, but not one that is hers for the asking.

You cannot be lonely if you like the person you're alone with. Dr. Wayne Dyer