Anyone willing to listen....?

okay....so my husband's best friend's sister moved into my parent's house a month ago. She's from the streets and had her kids taken away cuz she has a drug problem. If she goes to her younger brother, his wife will divorce him. She just has a causes problems. I really want to help her and get her on her feet, but there is no progress. I don't mind if she uses some of my stuff, but sheesh....my expensive shampoo and conditioner, expensive heat protector, panties, shoes, cigarettes, money. I don't ask her for anything because I know she doesn't have that much to give. But lately her and my husband have been spending toooooooo much time together. He doesn't take me out anymore, he'd rather go to places with her by himself, or whenever we get a chance to do something together, he either invites her, or she invites herself. I don't fell they're messing around, I just feel he pays attention to her more and gets everything she wants first before my son and I. I have no one to talk to except turning to strangers for advice. I know if I bring this up to him, it's going to escalate into a huge argument. She plans on moving in with my husband and me and live with us for the next 3-4 years. She's 6 years older than me. I just feel she wore out her welcome. My younger brother no longer has a room to sleep in. He has to sleep with my parents (14 yrs. old), cuz she stays there. There is no room for his clothes anymore, so he has to move everything to living room. He buys her outfits, gets her hair done, her make-up done, buys everything for her kids. He buys diapers and wipeys and necessities for our son, but I have to get on my knees and beg him to buy a toy for our OWN FCKING SON!!!!!!!!!!! We went through this with one of his friends, and our marriage was on the verge of divorce because of him. I'm just trying to keep my cool with everything and not blow up. I went from smoking a pack a week, to a pack and a half a day. I am soooooo stressed out. I'm ready to pack her sht and throw it the fck out. I apologize for the dirty language, but that doesn't even scratch the surface on how I feel. They're at the bar right now and he's paying for all her alcohol. Anyone with advice to give someone with a very bad temper about this situation, I will greatly truly appreciate it. Thank you for listening.