How to go about taking a parent to court without adult sistance? (more info)?

I posted a question like this earlier but since some people want to know moew fine i will tell you. I have a mother with BPD (borderline personality disorder) She is always calling me and threatens me and my other families lifes. She left me on the side fo the road 3 years ago and has never came back but only for her convenience. i get no child support and my dad isnt doing jack about it becasue i am afraid of how she will react to it all. i sick of her being a dead beat and making ehr little friends think she is the perfect mom when she knows damn well she isnt. My dad cant take ehr to court because he doesnt want to waste a heap load of cash on her. I want to do something and i want to know about how to do so. I dont want any critisizme for wha ti want to do. you haev onyl ehard half of my story ok... so dont go and say something if yu are nto sure. i just want help. im only 15.