My ex gfriend just had our baby today and she won't let me see her. Where, what do I do, in order 2 c my child?

My exgirlfriend, well a week ago she was my girlfriend and we've lived together pretty much throughout the pregnancy except for the last month. She left and we were on a break per say. Still talking on the computer and phone, saying our I love yous. We would talk about the baby and how I will be there and I wouldn't miss it for the world, and she agreed that she wanted me there. But since Feb. 12 she has started dating someone else, and really blindsided me. But one thing is certain, the people that got us together ( her parents ) are the one's that have influenced her to start seeing this guy, because they don't like me anymore. So today, she had our baby and I went to the hospital and they wouldn't allow me to see her or the baby. I asked if my ex had personally said that and the nurse said yes. So now I know that I am the father of this little girl and I know that she has got to be the most beautiful thing in the world and I can't see her. I have never felt so much pain in my life until today. I don't know what to do, where to go, to get the ball rolling. That child carries a piece of me just as she does her mother. Please! Anyone help me out as for the info to fight for my rights. My exgirlfriend's parents are really out ther too. They will I'm sure make some crazy allegation up. They are substance abusers, their home is disgusting, DCF has come out there a couple of times, but gave them an exact time and date. So of course they would clean the house and use lots of bleach so you don't smell the dog urine and pee, or the raw sewage under the house because their septic tank has been byped under the house. 8 people live in that 3 bedroom house full of cigarette smoke. 3 of them are minors, I'm sorry I can't stand for my child to be an addition to that enviroment. What do I do?