Unsure on where to go from here. Need help!

Hello my name is Tyler. I'm 22 years old now and I live in a small town in North Dakota. About a year and 4 months ago me and my girlfriend accidentally got pregnant. We decided that we would not get rid of her because she meant a lot to us even though she was an oopsy baby. We had a lot of rough times during the way even before she got pregnant. She is bipolar and she likes to either be depressed a lot or very aggressive. She attacks me and turns around to put on a sad face for her friends and family making me look like I was the source of everything. Lately she moved out into her own apartment with the baby and I live on my own. She does not take care of her apartment, the dog she has poops and pees everywhere, she does not clean up, and she is lazy. Over just this year she has bought useless junk from my bank accounts or credit cards. She will want something and if I say no she will throw a fit such as a 5 year old might and say I don't love her or care to make me feel guilty. I have lost a very large amount of money this month and my credit score has also dropped. Unfortunately lately she has become very aggressive. I was making supper one night in her kitchen and she began arguing with me, I knew she was upset so I stayed calm in order to help me. She became more and more violent and backed me against the cupboard and I told her nicely to back away. She began to yell and curse at me and push me around. I still tried to remain calm but she shoved me into a closet door and choked me until I had to push her away and yell at her to stop. She then came at me and bit my shoulder and hit me in the lip. Both spots were bleeding but, after the fact she started crying and acting scared of me like I had hurt her and it was my fault. I told her I was done and I didn't want to be with her anymore so she ran to the kitchen and put a knife to her throat as if she was going to kill herself. Ever since then I don't feel as if there is a connection with us anymore. I learned that most of the time my daughter is with her mom and she is at her apartment playing video games while she has time off. Her mom seems to be the one always taking care of her. I don't live with her because I feel scared she might hurt me but I want to get custody of my daughter so I can make sure she is safe and doesn't have a horrible childhood. I want her to have someone who cares like my parents did. She grew up in a home with a abusive druggie father who beat her and her brother and then finally left. Her stepfather was an alcoholic and very abusive to her mother. I guess the conclusion is that I am scared to make that first step because I am fearful she might hurt me or our daughter. I don't see the relationship working anymore as it is dragging forward and nobody is happy. I would also accept a 50/50 custody over my girl because I feel inside she somewhat still deserves a right to see her. I'm looking for advice on how to talk to her without a domestic violence situation coming out of it as well as maybe some legal advice on how to make sure I do everything correctly as I am only 22. Thank you so much!

I'm not sure if i said earlier, however her mom has our child most of the time. She always seems to have some excuse not to have her at her appartment such as, her wrist hurts and she doesn't want to drop her or shes sick and she doesn't want to get her sick as well but yet she will go visit her at her moms house. I get to see her maybe 3 times a week for 2 hours about because of this. She has had some domestic issues with her mother. Shes hit her in the face during an argument and gotten very physical in front of my daughter. Her mom threatened to admit her to the hospital on suicide watch several times. She has told me in private that she doesn't believe her daughter can raise our daughter alone safely. Whether or not she would support me in court I doubt it. I don't want to take the baby completely away from her however if we are split up I don't believe she could put our daughter first before her emotions. Thank you for your help! I very much appreciate it.

Social services has kept a close eye on us. Her mother had issues in the past with her so they automatically have taken us in. I had spoken with a local lawyer a few months ago now and I had tried to make things work but obvoiusly that hasn't helped. Should I make my first steps with social services or a lawyer? I believe trying to make a plan through social services would be a cheaper solution for both of us, yet still be all legal and documented.