I agree wholeheartedly with Bryson...I, too, was raised Christian, and still am a Christian, who also practices wicca. Please run like the dickens away from this woman. She sounds really off-base, and she's bordering on being abusive to you.
Anything or anyone who tries to instill fear into you is doing what Christians like to call "The Devil's Work." Do not believe lies---anything that is or sounds racist, judgemental, or strange to you probably is JUST THAT. You know in your heart what's right and what's wrong. Ask God to give you strength and courage to stand up and do what's right. You have to take care of yourself, not this woman, and not your dad. I hope to God this isn't some kind of cult.
I was raised in a Christian household and I stopped going to church once I turned 18. Just wasn't my thing but I know how it is being afraid to be your own person basically. Anyways,I don't believe you can sell your soul,but binding is possible. I wouldn't reccomend it personally.