There are several possible scenarios once the FNC's term expires.
The term of the council may be extended. The current FNC term was originally supposed to end in early 2009, but its term was extended from two to four years through a constitutional amendment. An emiri decree could allow the current FNC to serve for four more years, essentially a second term.
The council could also go on a "parliamentary holiday", with no FNC sessions being held and only the council's secretariat operational. This would result in a void, with the nation operating without its input. There is a precedent for this as well. Before the current FNC was formed, the council was out of session for about 23 months.
Elections may occur some time during the parliamentary recess, with perhaps new members being seated in October, in keeping with FNC tradition.
The final possibility is that the country does away with the entire election process, choosing instead to appoint all the members.