One thing you can do to improve her chances is feeding her a raw, high-protein diet. There are a lot of good suggestions out there from vets like Dr. Billinghurst. Not eating will be a problem later on, so if she does not want to eat her new diet just give her anything. No, I cannot tell for sure with a grade III mast cell tumor. Less than 10% of the dogs live more than five years, but as she is already ten that does not mean much. As far as a ramp, just make something at home with a sheet of thick plywood. You do not have to buy something from a pet store. Make sure the ramp has boards going across it so that she has adequate footing when she is climbing up into bed. I wish you the best of luck.