My heart goes out to you. I own 5 cats and my terror is not having the money if they need vet care. I have no credit cards (and no bank account, right now).
It's interesting (kind-of odd) that your pup has been checked out twice, but is still unwell. I know next to nothing about dogs - but there actually is a pet board here on the forum. You can find it under General Chat. I'm sure you will find input there. I will try to get your post moved for you.