Emergency, My Baby Was Attacked!

My name is Holliana and last night taking my dog for a walk turned into a nightmare. We exited the house and were by the driveway when a much larger dog came around the other side of the car and immediately latched on to Luna. The dog had no collar, my baby was on the leash. My luna is medium sized, the stray was very large but slim like a shepherd. I was able to avoid getting bit myself but my girl Luna has lacerations all over her body. She also is having trouble walking, they had to gernie her into the vet. I have not been allowed to see her since they took her back. The estimate of what she needs is $2,581.80 but they said that it could be higher if she ends up having any broken bones. As of this morning they called me to let me know she is stable but she needs surgery. I'm in between homes right now and it has been a struggle just to keep her with me please help our baby Luna.