You must ensure your name is on the birth certificate - this will automatically give you Parental Responsibility so you have a say in your child's upbringing.
If the mother refuses to put your name on the birth certificate you can get a court order. It is only in very rare circumstances the order is refused.
In the meantime, be prepared to financially support your child. If the mother refuses money, open a separate bank account and deposit money every month in to that. Keep a record of all money paid in, and how any withdrawals are spent.
If the mother refuses to let you see the child, a court order will give you contact righs. Once again it is very rare for this to be refused. Without pressuring the mother, get your parents onside and involved - they are grandparents, after all.