Poor girl. Until the vet can get out there to see her, I would try giving her a variety of things. I realize not the best solution, but the best one can do when not sure what's going on. Unfortunately, her leg weakness/issue could point to a number of a different conditions. Definitely give her vitamins (particularly B vitamins) and some sort of energy boost (karo syrup, nutridrench, etc.). Yes, she could be walking like that as well due to a urinary infection. You could start antibiotics if that's something you suspect. That will also cover any other infection that could possibly be the culprit of her problems.