Short Board Members

Peter,

Your Articles of Inc or your Bylaws should have requirements for filling the missing Board members.
To make short work of this and to have a quick answer, the 5 members may appoint members to fill the vacancies. Also, see if you can find interested members to step up but appointment is how it is done. Below is the Chapter from Florida Not For Profit Articles of Incorporation which is what your association is filed under. This is what you follow.

617.0809 Vacancy on board.--

(1) Any vacancy occurring on the board of directors may be filled by the affirmative vote of the majority of the remaining directors, even though the remaining directors constitute less than a quorum, or by the sole remaining director, as the case may be, or, if the vacancy is not so filled or if no director remains, by the members or, on the application of any person, by the circuit court of the county where the registered office of the corporation is located.

(2) A director elected or appointed to fill a vacancy shall be elected or appointed for the unexpired term of his or her predecessor in office. Any directorship to be filled by reason of an increase in the number of directors may be filled by the board of directors, but only for a term of office continuing until the next election of directors by the members or, if the corporation has no members or no members having the right to vote thereon, for such term of office as is provided in the articles of incorporation or the bylaws.

Or change your by-laws because five in plenty.