Poor things
If they were mine, I'd sell anything of value I had to get them help. Have you applied for Care Credit yet?
CareCredit Healthcare Finance - Payment Plans and Financing for Cosmetic Surgery, Dental, Vision, Hearing, Veterinary & Other Medical Procedures
If you truly really cannot come up with the money to help your pups, the kindest thing to do might be to surrender them to a Yorkie Rescue, where they'll get the medical help they so obviously need. That's what I would have to do if faced with anything major that I could not afford. It would be very very hard, but I love my doggies and would not want them suffering just because I don't have the money to help them
I'm so sorry you and your pups are going through this