Since you're not going to keep her, at the very least, be sure to put the effort into finding her a good home. Maybe you could start looking now. I don't have a lot of money, and both of my cats are on medication, but they are my children and I chose to be a pet owner. Sorry if I sound judgemental, but we have a responsibility to our pets, and if we aren't going to be committed to them, we have no right to adopt them. If she's holding it for 12hours while she's in a cage, then she needs some retraining. It could also be behavioral since she's alone so much and maybe your vet could recommend something. Maybe you'll have to get up at 3:00 am for a while to let her out, and then let her out again when you get up, and then before you go to work.