Try this: Each time you see her go out of your way to say hello and compliment her dress, hair or perfume, something sweet ... Old ladies love that sort of thing. Do this for a few weeks or so and hopefully some of your kind words will rub off on the old bag!
IF NOt: Bake her some brownies laced with Laxatives and tell her to keep the fat jokes to herself.... or You could just tell her she not being very nice and save the brownies for yourself.
