I'm so sorry you are dealing with this. It must be so painful to watch your wife deteriorate into someone who would do things you wouldn't fathom. Meth IS the worst IMO. I've seen people destroy families and relationships over it.
I would suggest that since your daughters are starting to open up, that you get them into counseling ASAP. There's probably a lot they've seen in the little time that their mom did drugs. They need a professional to help them sort through it, and understand it.
I'm praying for you and your girls.
Me 36 Husband 35 D5 S2 separated: 10/29/07-present Served divorce papers 1/22/09 "When the world gives out beneath your feet, it is time to learn how to fly."