Some jurisdictions such as Missouri have what is called a relocation statute. It specifies that if either parent moves (even across the street) must file by certified mail, sixty days in advance of the move a letter directed to the other parent describing where they are moving, why they are moving, the new telephone number if known and a proposed change to the < parenting time > and transportation schedule. If the non-moving parent opposes the move they can file a Motion in Opposition to Relocation, though the burden of showing that the move is in the best interest of the children is upon the parent seeking to relocate. Often a Motion to Modify custody is filed at the same time.
I am not licensed in Georgia and therefore cannot speak to the specifics of their statutes. If it is not possible to prevent the move, it may be possible to modify the transportation provision. The key issue is why is she seeking to move and is she against your involvement in the children’s lives.