The County Commissioners of Charles County, in addition to, but not in substitution of, the powers which may have been or may hereafter be granted them, shall have full power and authority to acquire by purchase, lease, condemnation, gift, or devise real or leasehold property or any interest therein needed to establish county roads; to return to the original owner or his successor in interest any real or leasehold property no longer needed for road purposes; to sell at public or private sale any real or leasehold property devoted to county roads when no longer needed for road purposes; and to exchange any real or leasehold property devoted to county roads and no longer needed for road purposes for real or leasehold property needed to establish county roads. Any such sale or exchange shall be advertised for at least twenty (20) days before the date of sale or exchange.