I am so sorry to hear this. It seems every second day we have a member posting here about their dog and osteo.
We've discussed this many times, and many of us feel, that even after putting the dog through amputation, chemo, treatments, and spending a lot of money...you still have a dead dog in a few months. These treatments just buy you some time, not a cure.
I would make sure that she has good pain medication, and then I would spoil and love her and make her last days enjoyable.
We discussed this on this thread:
http://www.rottweiler.net/forums/vet...bly-cancer.htm