To go anyway from the Marriott, you'll need a taxi or limousine. Unfortunately, in this country it's often difficult to get a taxi. So if you want one to go to a mall from the hotel, you gotta order one hours (days...) in advance (Tel 4588888). Especially in the busy times (morning/early evening) it's very hard to find one. The limousines are always available in front of the hotel. For the way back, as Fatcat said, most of the times you'll have a taxi in front of the Mall and if there is no taxi, one will come after a few minutes.