Hi Lox
Do not have any interaction with her dealers. For one it could be misread if the dealer is under survalience & 2nd it may get you killed. A guy I grew up with told his girlfreind's dealer (same situation as you're in) to stop selling to her. The dealer shot him in the head.
I don't think you're really taking this as the drastic situation that it is. You're concerned about the mother's health, welfare & emotional well being, I got news for you, she's not interested in you or your daughter's. Your daughter will get over having a junkie for a mother but she won't get over any harm that's done her by you taking this to lightly or not moving on this swiftly enough. If you need to expose her at her workplace, do it now. If you need to do anything, do it now before your little girl's the worst for it. Please don't take my comments lightly. As I said this was my life, it is also my younger brother's present life (only he is the cause)you won't come closer to anyone else who has lived what your daughter will live. Good luck. PM me if you care to, I'd be happy to help in any way.

Barry