You dont need to go to Bldg 1 for renewal if it is during first month of visit. Just get the forms typed and go straight to bldg 4 with passport and your QID and they will do it for a maximum of 5 months more. Fees is QR 200/- per month.
All the tiem required is the time you spend waiting for your turn. Counter person will do it immediately as soon as your turn comes.