What does this mean? AMENDED PETITION:to Establish Paternity, Periods of Responsibility, Custody and Child Sup?

just wondering. this is what shows online when i look up my case... this petition was originally opened cause income support went after me for child support and now i see the above. what does it mean and is it gonna cost me anything and how much? i haven't seen my son in 3 years, but found out that my ex gf is in rehab... haven't paid any child support either in that time, but want a hearing for custody of the boy. i got served from my ex gf's parents wanting guardianship, saying that neither of us are fit basically. does the above have anything to do with my case, or is it their case for guardianship?