A320's are coming from leasing companies and Airbus, the MD90s should be phased out against the delivery of the Airbus aircraft.
Classics have to stay until the A330 replace them, this will begin in 2012, although judging by the number of non-owned A330/340 aircraft sitting in Toulouse, this might be a lot sooner!
With 100 new hire FO's per year (Saudi nationals only before any decides to apply) They will have sufficient FO's, the Captains will be hard to find, but with the introduction of Sabre AirCrews and implementation of new work practices, it wont be an impossible task.
The fun starts just after Eid, so sit back and enjoy it
Mutt