Here is how I replied:
I completely understand where you're coming from, but I don't think I can help you. Perhaps try salary calculators found on salary.com or careerbuilder.com?
At first I wasn't going to reply at all, but I didn't want to be rude (even though she was pretty rude by even asking). The more I thought about her email the more I think it was just tacky. And lazy. When asking for a raise or negotiating salary ya gotta do some legwork! Silly girl!