Child Custody - Pennsylvania

My question involves a child custody case from the State of: Pennsylvania

I am desparate for legal advice in a child custody case. I will try to keep this a brief as possible.

2 years ago I filed for custody of my 2 girls after I found out that they were being abused by their father's girlfriend. I currently have physical custody of the children and they see their father every weekend.

We have been in front of a mediator 3 times over the last 2 years and every time I have won and have retained physical custody.

I just received papers in the mail that my custody case is now going in front of a judge for him to decide who gets custody.

I have exhausted all of my money fighting this case so now I am left to defend myself with no attorney.

I also just recently found out from my oldest child that about 7 months ago when she was spending the weekend with her father, someone broke into her father's house looking for drugs (yes it is suspected that he is selling drugs), and this person held a gun to my childs head. Apparently what eventually happened was that my daughter's father was able to talk this man out of the house without incident.

I am also being told that a few months after this happened another person broke into his house once again looking for drugs. How can I prove this in court and prove that my children are and would be in constant danger if they lived with their father? I am also afraid for him to even have visitation for fear the kids could be in harms way.