
Myraf, so sorry to hear this. Many of us have been there, and this is a horrible disease. However at age 11 if the disease is in the very early stages you could be lucky and find that you still have her for most of the rest of her natural life, as DM can progress quite slowly, and also has a 'plateau' stage, where for a while they do not seem to get any worse.
I don't know what stage your girl is at right now. Anyway, below are a couple of links, the first is to a harness which although I haven't used it, looks as though it would be brilliant for a DM dog, as you can leave the back part on all of the time, it is supposed to be comfortable enough. It is made to measure (from the USA). A good harness just to help steady them in the later stages is incredibly helpful. The second link is to a DM support website. Again, it is a US website, started by someone who has had 2 DM GSDs, and IMO is one of the most knowledgeable people on DM, in collaboration with Dr Roger Clemmons who is a research vet at the University of Florida who has researched and worked extensively with DM, and came up with a 'protocol' in terms of supplementation for DM dogs. There is a forum and a range of sections including one on diet and exercise regimes formulated by Dr Clemmons. Have a good browse through the whole site if you will, especially the diet and exercise protocols.
http://www.hartmanharness.com/http://mzjf.com/I hope this is of some use to you. You have my heartfelt sympathy at having to deal with this disease, but I do hope you will have a progression which is slow and which will allow you good times with your girl.