The Secretary is directed to acquire in fee all other privately owned lands added to the park by and pursuant to sections 251e to 251m of this title, and to acquire within three years of October 21, 1976, so much of such lands as can be acquired by donation, exchange, or purchase, to the extent of available funds, and to report to Congress on the third anniversary of October 21, 1976, the estimated amount of appropriations which would be necessary to acquire the remainder, if any, of such lands by condemnation. The compensation for such lands shall be their fair market value on the date of their acquisition, taking into account applicable land use regulations in effect on January 1, 1976.