Fostering daughter of formally close friend, how to navigate?

So we recently have had our 20 month old god daughter placed with us and are in the process of getting a 30 day foster licence. Bio mom is (was) an old family friend who has several issues, Severe Alcohol abuse, mental health issues stemming from trauma, along with slight mental disabilities. She lost 3 kids previously due to these issues along with a domestically abusive ex, who is Bio dad to baby girl. Bio dad is in prison so is out of the picture for a long time. Both Mom and baby girl lived with us for 10 months. Bio mom was supposed to get back on her feet, but she refused. In August I came home from work one day to find the doors open, the house an absolute disaster, baby girl naked, sticky with sweat, drinking curdled milk, eating cigarettes, and picking Prozac up off the floor. Mom was completely incoherent, and had been for hours. We had to report it. The county took custody, but Mom was allowed to keep baby girl with 24 hour supervision- which was mostly us. (I have previous certified child care experience.) and court ordered sobriety. Mom kept expecting us to cover for her, and after a couple incidents of dumping us with baby girl, We told her to find her own place, and the county decided to place baby girl in care. No one of her family wants baby girl or is qualified for care, so we received placement because we are "like Kin". The goal is reunification. The foster licensing has been very time consuming- trying to fit it all into a 30 day period, means we are meeting with the foster care coordinator 2 times a week and are barely squeaking by, we were so not expecting to become foster parents at this time, pre-placement training, minor home fixes, doctors visits, tons of paperwork, etc... Plus meetings with the social worker. On top of that we are supervising 4 hour visits with Bio Mom, 3 times a week. Just feeling overwhelmed with the amount on our plate at the moment. Bio Mom keeps asking for us to provide milk , juice, snacks, and stocked diaper bag for her visits. She views us as a personal taxi service and gets upset when we tell her no. We are not getting reimbursement this month for baby girl, so our finances are already strained. Bio mom keeps drinking and DH has been obligated to play babysitter to her, but that means he is missing out on moments with our own family (we have our own tween son also). Bio mom expects us not to tell, and keeps thinking this is just a game for her to navigate until she gets baby girl back. She keeps accusing us of stealing baby girl, instead of acknowledging her own behavior. She doesn't understand that the we have to report it. Or that She has burned bridges with us, and can't consider her a friend after all she has done. We are at our breaking point with Bio mom. We can't continue to support her getting help if she continues to walk all over us in the process.