If your not going to use protection she could have used morning after pill which can reduce chances of pregnancy up to 95%. Looks like you guys got extremely bad luck, or just retarded, or a troll, or if this story is true she may have gotten preganant on purpose.
Good luck taking it to court. The positive is that maybe you can successfully fabricate and convince the judge that she's harm to the child. And if you fail you'll probably end up tarnishing your relationship with your boy's mother. And she'll end up getting another man signed up on the birth certificate as the boy's father.