Child Custody Florida

I am divoced for about abit over a year now but originally separated not legally since january 2006. We filled a mutual agreement divorce in orange county florida and used the courts standard visitation stipulations, one weekend every other week have summer vacation, half winter vacation. I am living with someone now, and we have a 2 bedroom apartment where also my step daughter (18) and her husband are temporary staying with us, they were kicked out by my stepdaughters house by her dad because he needed to make repairs to the house and need it to sell it. when my kids come to visit i let them have my room. My kids are 12 girl and 6 boy. they love when they come here. I honestly cannot afford a bigger apartment, Just recently, when i went to pick up the kids told me that untill i get a bigger place that the kids have each their own room she is not going to let me keep them overnight. I was wondering, Is there a law in Florida that allows her to do that or can I ask the judge to impose the agreement in the divorce decree. I dont know what to do, my daughter was crying and she (my ex) always threatens the kids that they are not going to see me in my shedule time just because my daughter did something or disobey her in something. My ex have my kids (specially my daughter) very upset and nervous, always screaming at them and imposing to them in a way i believe is not healthy. I on the other hand have my issues with my kids but i rather sit down and talk with them than screaming, besides my daughter feels bad when her mothers husband talks bad aboud me in front of them and also constant yells at them. please what can I do? I want to do what is right and lawfull. Just when this last incident my ex was yelling at my daughter in the front of the house in front of the neighbors about an issue with her husband and my ex maniacly told my daughter to shut up that she didnt want to hear her, and I told her (not screamin) that she shouldnt talk to our daughter like that, my ex went balistic and told me to leave, that i was the reason my daughter was so rebelious and that i was taking out her AUTHORITY. That she was not going to let my see the kids again and for me to take her to court. I told her that between her and my kids i was there for my kids. I really dont know if I was right or is she right, please help.