Coral Mall is on recto for Autopiste San Isidro, just before the Charles intersection. You can get there by Taxi for RD250, 200 if you know your spanish a taxi.
Just out of interest, what are you expecting. This is not a Mall as you will know it. Golds Gym upstairs, and cine and a few eateries on the second with over prices terrible kids games and a couple of shoe shops with a few banks and a terrible furniture shop on the first, Oh, you have Bravo supermarket. Just wondering why the effort if you cant drive. Its a place I call at the bank and then keep driving.