How am I able to stop her from doing this?

here is where it gets to the point where you need to just stop showing her your work. Especially if shes getting recognition for it. That would be a deal breaker for me..she steals from you plain and simple. She sounds like an ignorant biach.. if you have confronted her already and she still wont stop. i wouldnt even give her a chance to shut you out. i write music, and if someone copied one of my songs, and it was obvious , id probably break on guitar on his face, Especially if it was my music getting popular, but thats not what im suggesting. now its time for you to close HER off. don't show her Anything, and start putting your art work out there. you have to sign your name on your art, and present it to your friends yourself. and if she asks why you dont show her anything, tell her the damn truth.. if it causes you your friendship.. so be it. shes a theif anyway