So sorry to hear the awful news.
Make every minute count now. Take some pictures, make a paster cast of her paw, cut a lock of her hair...so you will have things to treasure of her.
Spoil her rotten...let her eat anything she wants...if she can. A cheeseburger at McD's seems to make them very happy.
Love her and enjoy your last times together.
You are doing the kindest thing, and ending her pain.
Gina