[gemy]

Wow, I certainly hear your frustration. But to be blunt, I find this situation very very sad, for all concerned; but particularly this dog. It also sounds like you have a good bit to work out with this girlfriend of yours. For example the different attitude you have on biting, and children, and btw I agree with you, biting is totally unacceptable behaviour no matter what size the dog is. If you have tried all the techniques that you know to eliminate this behaviour, then I strongly suggest you get a trainer into your house, to help you solve this problem. There is no MAGIC solution. There is only your effort to find the way to discipline, consistenly, persistently, and calmly. Reward for the good behaviour. If this dog growls and snaps at you, it's crate time, or a time out. It sounds like to me that this 6yr old dog has gotten away with a lot of bad behaviour over the years. That is the owners fault, and not the dog!.
I've been trying to figure out from your posting, just when anyone is at home. From what you've written, it does sure seem like this dog doesn't get much exercise or time and attention. A bored and unexercised dog, is as you know much more likely to act out.

In terms of food my 6.5 lb boy gets 1/3 c of food a day, and small amts of training rewards, when we are out for walks and during obedience training.

In terms of pooing and peeing in the house and crate, common sense tells you that you can't crate a dog after feeding for 8plus hours and not expect "accidents" in the crate. Get an Xpen for her, bed in one area, peepads in another area. How about getting in a dog walker to give this dog some exercise and an opportunity to eliminate outside.

And you are absolutely right this dog deserves a better life, than the one she is living right now. If you two can't give this to her, please surrender her to a reputable rescue.