I'm very sorry to hear that she has passed. I was reading this thread last night, and was practically crying 'cause I wanted to be able to do something to help.
You tried to do the best you could, I can tell you loved her.

I guess the final lesson is for your girlfriend. Don't get a pet if you can't keep it in your own home and provide it with love and at least basic care. Shots are very important, especially for puppies. When warmer weather comes there is flea/tick protection, heartworm protection on top of a good quality dog food and the annual physical and shots. It's not inexpensive, by any means and people really need to think about how they are going to care for a pet, not just get one impulsively 'cause they think it's "cute".

Again, my condolences.