I have been with a girl who has had my baby and I am no longer with her but have visited the child on a numerous of occasions .I have found out she has registered her birth without me knowing and have not been put on birth cetificate what rights do I have

If your child's mother is willing to put you on it, then call the city clerk. They can direct you where you have to go for birth records. If she is not willing I would imagine friend of the court, or get the advice of a lawyer.

Good luck

You go to court and request paternity testing. They will order a DNA test to prove you are the father and you can have the birth certificate modified to reflect it.

At that point you can also have a visitation schedule ordered and you will likely be required to pay child support.