Losing my mind with this dog!!

Elizabeth • Mommy of one beautiful girl, and twin boys (:
Ok I was very nice and offered to watch a friends dog because her other friends house was infected with ticks. She didn't want her mini chihuahua or her son to bring the ticks back home. Well I offered to watch the dog. Well, she lied about the friends ticks, she's been bringing her child over there everyday. I helped raise this dog when she first got it. Taught it to go outside, ect. Would walk her 4 times a day. Well, anyway, I'm watching Gracie, and they have her potty trained to go on pads!! Problem, house now smells like urine, and I keep finding crap everywhere!!! She will not go outside. I've tried. Oh and she tried to tell me the dog needed to sleep next to us. Uh no. I've been allergic to Gracie since day one. She knows this. Oh and let me just say, we taught her to sleep in her cage when she was a puppy so that way she wouldn't get stepped on i the middle of the night. I get that I'm hormonal. But I really am losing my mind. I raised this dog at first, then she took over once she worked less, and got pregnant. Great. I thought she would continue actually taking care of this dog. Oh forgot to mention, she no longer walks her because she doesn't want to. She refuses to give her a proper home. I can't keep her, I'm allergic to all animals and soon all my time will be taken co pletly. I know I shouldn't be upset with Gracie,it's not her fault,  but I don't know what else to do. She goes home in 2 days. Any helpful hints to get her to at least go on the puppy pad.