The gold souk is on Al Ashat St. which runs one block south of Ali Bin Abdullah St.  Al Fardan Ferrari is a good landmark as is the bus station. The pigeon Mosque is just north of it also. LuLu's Hypermarket also has some  gold merchants and they list their prices ans there are little gold souks spread throughout Doha such as over on Al Diwan and Al Nakheel St which is near Sofitel.

Good luck.

Participant South East Asia War Games

Second Place