How much longer does my dog have to live and what can I do?

First, let me say what a wonderful pet owner you are to be making her last days as enjoyable as you can. I have a cat right now that is suffering from intestinal and stomach cancer and he is on his last days. He can only drink kitten milk and water and he is getting pampered until next Wednesday when we put him down. I believe that putting animals down is very humane and if they are suffering or in pain a person should do it. It sounds like you are really in tune to Skittles well being and know that she is not going to be with you long. It's so hard to make the decision as to WHEN, but just know that her memory will be with you forever and there has to be a special place for all our furry babies to go. It also sounds like she has some time left. Just re-evaluate her daily. If you feel that she is in pain or struggling you should take her in, but it sounds like you are making her last days as enjoyable as you can. Good pet parent!