How can i help her?

I met this really cute girl but i think shes on some serious drugs, she smells like strange chemicals and smokes way to many cigarettes but she seems to sweet to me. I think shes hooking too because i contently see guys go in and out of her house ive never seen before. I want to help her but all she wants is money and drugs, she even offered to sleep with me if i payed her but i couldn't do it because i felt so bad for her. I give her money sometimes so she doesn't have to do things with strangers for it but i cant afford to keep it up. She also has a 2 year old son that i worry about and take care of sometimes when shes out but i'm not really too sure what to do about him.

I like her but not her decisions, what can i do?