The administrator, with the advice of the commission, shall employ all assistants, architects, engineers, janitors, custodians, and caretakers necessary for the efficient and economical discharge of the duties imposed by the Nebraska State Capitol Preservation and Restoration Act. All such employees, except for the administrator, shall be included within the State Personnel System. The administrator shall purchase, through the materiel division of the Department of Administrative Services, such supplies, material, and equipment as may be necessary for the proper maintenance of the State Capitol and capitol grounds. The total expenditures for such purposes shall not exceed the appropriations made therefor.