How do I as an unmarried father with court ordered child support established get visitation rights for my 2 children?

Under the U.S. Constitution, as interpreted by various Supreme Court decisions, if you are the biological father you automatically are entitled to at least reasonable visitation (unless you have been convicted of child abuse as to the children or some other extreme facts).  The child support is irrelevant to your right to reasonable visitation.  Most courts have interpreted reasonable visitation to at least mean every other weekend, depending on your and the mother's schedules.  You should search for child custody lawyers, and have them file a petition to establish a visitation schedule.