So sorry you are feeling bad about this. As a longtime animal rights advocate I know it is really painful, certain people can empathize with animals and feel their pain and suffering while others seem not to notice at all. I hate to say that I go out of my way to avoid situations that I will find disturbing, I never watch videos put out by animal rights groups (I don't need to, they'll just give me nightmares), don't go to shelters unless they're no-kill, etc. You can make a difference however, I would say:
1. Check with the local laws as some other people mentioned, put in official complaints to the people who run the market, see if you can find out where this woman's business is located and send her complaints as well.
2. Join either an animal rights group or local shelter, volunteer to either educate the public or help take care of unwanted animals in the shelters.
3. Join protest groups, you could even protest this woman's stand, but you have to be prepared that many people will see you as the crazy one and not her.
4. Of course take good care of your bunnies and other animals, and set a good example for your friends to look up to, as someone who is truly compassionate.
That's all I've got! People like us can either make a tiny mark by helping the animals we can, or waste a ton of time wallowing in complete misery. It's depressing, use your outrage to make a difference