Copyright/Plagiarism??

Here's my problem. Someone purchased my 2007 copyrighted pattern in Oct 2011, made the item and, posted it on YouTube a month later, mentioned that they bought the pattern from me, and where from one of my pattern stores they purchased the pattern from.

  Then, the next month, they not only posted a plagiarized free version of the same pattern, but linked it to a video tutorial on YouTube.

  By calling it by a different name, changing some of the abbreviations like sc dec to sc tog (the same thing!!), saying she's justified by making it 'similar', but listed it as a 'orginal design'. Trying to reason with her is useless, and she's done something similar with a different pattern.
I'm concern that if something isn't done, it sends a bad message to anyone who feels justified in doing the same thing to any other designer!!
It's the first time it's happened to me. I'm sure you've had people tell you that they've either had a similar idea, and/or claimed they thought of it too, but if you don't publish it, it's just a idea.

She claims she' made a 'similar hat for her husband a couple of years ago (she list she's only been crocheting for 3 yrs!), but never got around to writing out a pattern....well, going over the pattern myself, it's clear she doesn't know how to even copy one very well.

Posting the pattern as 'free' doesn't resolve you of any wrong doing. In fact, it makes it worse.

By giving it away for free, it takes potential customers from me.

Sure, it may boost your ego, and may attract a lot of people to you, but pretty soon that gets old, and eventually, if you keep it up, one's true colors will begin to emerge.