The public defender may appoint as many assistant public defenders, who shall be attorneys licensed to practice law in this state, secretaries, law clerks, investigators, and other employees as are reasonably necessary to permit him or her to effectively and competently represent the clients of the office subject to the approval and consent of the county board which shall fix the compensation of all such persons as well as the budget for office space, furniture, furnishings, fixtures, supplies, law books, court costs, and brief-printing, investigative, expert, travel, and other miscellaneous expenses reasonably necessary to enable the public defender to effectively and competently represent the clients of the office.