craftgrrl | Reproduction of my work

*Update*
I have talked to the girl who was making copies of my bag and she was happy to remove them from her site and assured me she would not make more copies. Please do not send her emails ~ I feel like this is resolved. I do appreciate all of the great suggestions I got from everyone and will definently save the comments if I need to do anything in the future.

Well, one of my customers pointed me to a website that is making reproductions of one of my bags.
I think that suing them would cost me more than I would get from it (though it would be a good warning to others), so I am trying to figure out what to do about it all. Here is my bag ~

And her bags ~

I think there is no doubt that this is a copy, yes? (considering I drew out the design myself)

I emailed the girl nearly a week ago, telling her that she needs to remove her copies of my bag (and not to do it again). I have gotten no response from her, and pretty sure I will not hear from her. I am planning on posting on several sites/forums online, including my site, telling others about the reproductions and that she should not be bought from. She also has a retail store that she recently opened, and I have the address and phone number for it. (I am worried that even if I can get her to pull the bags off of her site that she will just sell them in her retail store)

So does anyone have any suggestions on what I should do?

EDIT ~ COPYRIGHT LAW
For those who don't know, anything you create automatically has a copyright. Before you can do anything legal with it, you have to fill out a form with the copyright office (and send in $30). If I did decide to sue, I would have to file my copyright, but the item already has one either way. (There is lots of info about this in the mem's and on copyright.gov if you want to read more about it).

I JUST GOT AN EMAIL FROM HER ~
"Hi Tiffany,
I'm sorry for not getting back to you sooner but I've been out of town.

The bags you mentioned were originally created for a regular customer of mine who brought a picture of a bag she'd seen into my store and wondered if I could create one for her. I didn't ask her where it was from, many people come into my store with pictures of things for me to make, and I'm happy to do it for them.

I really liked the design and made a couple more for the store & site. Please rest assured I have no intentions of making any futher bags in this design. I never intended to "steal" someone's ideas, believe me as an artist myself I've certainly experienced it as well, so I apolozige if you felt that way. From your site it looks like you do beautiful work - keep it up!
with peace,
Emily"

I do think it a little odd that I just heard her (right after she recieved her first angry letter from someone on here) but it does feel nice to hear an apology.