I am a family lawyer licensed in Georgia.
You had the right to seek legal counsel during the divorce to properly advise you. First, if you want to see your children you should have sought visitation during the divorce action. Nevertheless, it is not too late to petition the court to visit your children. In the petition, you can inform the court of the lack of transportion. The judge may make concessions and order your ex to bring the children to you.
Finally, unless your ex is married and the new husband adopts the children, it is very unlikely that you can simply renounce your children.
I don't practice in your area of Georgia. However, you should seek legal assistance regarding the child support and visitation.