My foster daughter is driving me bonkers

I have a 17 soon to be 18 year old foster daughter. She is emancipation out of care in December and going off to college. She is afraid. Stupid me came up with the idea of a service dog for her numerous mental illnesses. What a mistake this has been from the beginning. We have been searching for the right dog. She of course wants everyone we see and falls madly in love and is devastated when we have to turn the dog down. This past weekend we interviewed a husky that our trainer recommended. The dog was perfect but just as we were about to sign the adoption papers, the trainer suggested he introduce him to his Rottweiler to see how the dog did with other dogs. The dog went crazy, very ferocious. So I said no. She tantrumed all the way home. Finally I could not stand it anymore and let her pick out this dog from the humane society. It could not have been a more inappropriate dog. Darn thing is so hyper. It is peeing everywhere and humping everyone. The dog is yippy and wakes the baby. But the dog is not the problem. She is. She is rude and disrespectful to everyone since bringing the dog home. Did not go to college the first day because her allergies were bothering her, and because she did not get any sleep because of this neurotic dog. Gets all bent out of shape if anyone touches her dog. We fight constantly about her taking him for walks. I have warned her repeatedly to stop yelling at me. She is six foot tall and three hundred pounds and uses her size to try and intimidate people. She is a second away from me disrupting her over a stupid dog. It is so ridiculous. All of our expectations regarding the dog were discussed prior to this but I should have known I was being suckered. I am furious with myself for allowing this to happen. I had worked so hard to get her to this point in her life, battling social workers that wanted to just institutionalize her. All summer I fought with her to get her GED , forced her to complete barista training and now have her in a good place for her future, only to be foiled by an adorable little dog that in no way will ever qualify as a service dog. I am just so frustrated. If we return this dog, she will fall apart and resort to violence. If she does not get her act together and keep up her school work, etv will take back her money and she won't have money for an apartment in December when she transfers colleges. Just really ticked at myself.