I am sorry to hear about Tara.
My name is Rebecca. I am a veterinarian, and will do my best to help.
There is a condition, called degenerative myelopathy, that is seen in this breed. It is a gradual deterioration of the spinal cord, and the dog slowly loses nerve function of the hind legs, and eventually can lose function of the colon and bladder. If Tara has DM, it will get worse, and pain medication will not help.
If she were my own dog, I would have her checked over by a veterinary neurologist, to be sure of the diagnosis. There are other condition besides DM that could cause this.
A veterinarian at the vet school in Florida, US has studied DM for years, and recommends a course of supplements and vitamins that have helped some dogs. Here is an article about his work and recommendations: http://www.drschoen.com/hopeful-news-for-degenerative-neurologic-diseases/
Here is another article about it, which also describes the blood test that can be done to see if she does have DM: http://www.veterinarypartner.com/Content.plx?P=A&S=0&C=0&A=2600
I am not seeing responses from you, so I will try another way to connect with you.