Farmville Expand Farm Locked

i want to expand my farm on farmville (facebook) to ‘big ole plantation but is says locked?

i want to expand my farm on facebook farmville to ‘big ole plantation’ and ‘mighty plantation’ but it says locked – coming soon so how do i unlock it? i am level 24 (18633). thanks xx

I want to do that do but that application is not available at this time.
They are probably still working on it.