well, following are the documents :

a. Arabic letter of no objection from your company/ employer for buying a car.
b. copy of your qatari ID
c. car seller's registration(car) card
d. your credit/atm card for making payments at the counter
e. Another arabic letter of transfer that you get typed out from typists sitting around the traffic Dept's office for a small fee ( say QR10/-)

The actual transfer takes about 10 minutes at the counter and you get your card of registration on your name.
That shud help ?