How do I file for custody of my son in Illinois?

First of all, please pardon the long nature of the question, but I wanted to make sure to include as many details of my situation as pable. My son's mother and I recently split up. We have a 15 moth old son together and up until about 2 months ago I was a live in dad/boyfriend and provided 100% financially for our family's needs. On Friday I got some rather disturbing information regarding a member of my ex's family that my son is exposed to. My son's mother has neglected to mention that her mother's husband is a convicted murderer of a 14 month old baby girl (roughly the same age as my son) and offender. She has put our son in this man's care and endangered him by doing so many many times. I just found this information out Friday about his past and when I confronted her about it she admitted to knowing about and keeping it from me during our relationship but she has bought into his "it wasn't me" story. Her whole family thinks there is nothing wrong with my son being around this baby killer and rapist. I called the police on Friday after speaking with my ex and her reluctance to agree to no contact between my son and her mothers husband, The police said that they can't do anything as long as the interactions are in a "family setting" and he is not providing direct day care/babysitting, however even the police said that this is a "grey area" as if my son's mother drops our son off at her mother's house to babysit, the husband will be there of course because he lives there. Since I wasn't able to get anywhere with the police I decided to call DCFS because I was told that they might be able to ensure this man is never again in the presence of my son. Today an investigator from DCFS called me to let me know he was going to make a visit to my ex's home and discuss the need for my son to be around this creep, but he even made it sound like there is nothing he could do if the guy served his time, ect. Now keep in mind, he is a registered offender in both Illinois (where we live) and in Oregon, where the crimes were committed. On his Oregon offender page it states that he is to not be around anyone under 18 years of age, presumably because of the age of his murder victim. Since it seems like I might have hit another dead wall with DCFS I have printed out and filled out all the doents necessary to file an order of protection and will be filing tomorrow morning hopefully to ensure this man can't be anywhere near my son, but I was told that it may be a "long shot" as most order of protections are for other reasons, maybe this was just a dumb clerk that I spoke with but I'm already planning my next moves if it fails. In either case, weather I get an order of protraction established for my son and this man or not, I am seriously thinking that my son's mother's judgment is too severely compromised to be the main caregiver for him based on her willingness to put him in a position that he has been exposed to such a person. Right now I am getting him every weekend, we have nothing in writing and no court orders for custody, also I am providing voluntary support, again, nothing in writing, just voluntarily. The first things you guys are probably going to say is "go get a lawyer"...well I have been on the phone NONSTOP since Friday when I got this information and I simply am not in a position to be able to afford one. I just don't have the money. I have asked my family but they have not been able to help with money either, so I'm on my own for now it seems. Can I ask for custody tomorrow morning when I file the OP? Based on her negligence and immediate danger to our son? I have asked the court what forms I would need to obtain to file for custody but they basically told me I need to have my lawyer draft the paperwork or basically "learn the law" and do it myself by going to a law library?!? Again, I am in Illinois, if that matters, and any suggestions would be greatly appreciated, I have been terrified all weekend and this week.