First of all I wold call a city inspector he will come and take a look at it. If it is deemed unfit he will condem the building until it is fixed. I also wanted to let you know that the mildew can he a health hazard and can be deadly too. If the mold gets into yourr lungs it can cause infection and can kill you. It is esoecially bad for small children and elderly.
I would go to the city and fast and I would get in contact with Legal Aid in your home town they are there to help renters with problems just like yours.