If you send your contact sheets to the copyright office with a $30 fee and their application filled out, you can sue her for copyright infringement or at least threaten to. You might wish to take the time to do some educating first about that, with her. The next time you do this, you also might want to have a receipt book and fill in the name/address/phone/email info on each receipt as you make the sale, also collect sales tax if your state requires it (you needed to do that anyway). Finally, you need to determine whether she goes ahead and does that by checking and printing out a copy of her web site.
