Can't remember how long the temporary airman certificate lasts for but you should have your licence back before the end of the validity of the temporary one.
I completed my FAA CPL Checkride on the 31st July 2003, the FAA IR checkride being taken four days previously on the 27th July 2003.
One day towards the end of September I received two letters from the FAA... yes that's two letters on the same day. Uh oh I thought, this doesn't look good.
Anyway opened the first one and it was my FAA PPL/IR certificate and hurridly opened the second letter to find my FAA CPL/IR enclosed.
What a waste of international postage!! The examiner was the same one, they probably received the applications for both certificates on the same day in Oklahoma... Still I didn't have to pay the FAA for the issue of the certificates so I'm not to grumble.
By the way if you haven't got a full FAA certificate yet then they are of the credit card type... very neat.
Best wishes,
Charlie Zulu.