Great that you're taking care of her. It's always shocking to see the level of scumbags that abandon their pets. It's not that difficult to take them to a shelter. Sure, they're likely to be euthanized, but that's still better than starving to death, getting eaten by a coyote, or being run over by a car.
A previous client of mine was a local Humane Society. They offer vet services, but are not a shelter. Idiots would abandon their dogs in the parking lot, not realizing the actual shelter is practically across the street. This is on a very busy 4 lane street in San Bernadino. One time I was getting tools from my truck and saw a small dog hiding behind a vending machine shaking. Come on now! If you had a lapse in judgement when you took in the pet, fine. But please at least make sure they're safe when you give up on them.
Also watched a customer leaving, kiss her dog before locking it in the trunk of a sedan. Ok then...