The Department may accept any allotment of funds by the United States, or by any agency thereof, appropriated to carry out the purposes of Section 131 of Title 23, United States Code, as amended from time to time. The Department shall take such steps as may be necessary from time to time to obtain from the United States, the appropriate agency thereof, funds allotted and appropriated under that Section, for the purpose of paying the federal share of the just compensation to be paid to sign owners and owners of real property under the terms of subsection (g) of that Section 131 and under this Act.