I really don't know about new airplane order.
So far we received almost half of the 44 new airbus. In 2013 they will come with the new sharklets. Last delivery should be completed in 2016.
Airbus A320Neo, B737Max they will be around in 2016 as well. Still too early to make predictions, plus Sharjah airport is too small for all this aircraft.
Rumours says they will build a new terminal especially for Air Arabia, like Easyjet is doing in Europe.
Cheers.