If you do not need international accounting firm, but just large Dominical accounting firm:
Job, Baez, Soto & Asociados
Ave. Lope De Vega, No. 13
Edif. Progreso Business Center
Suite 503
Phone1: (809) 412-0420
Phone2: (809) 412-1072
Fax: (809) 565-4123
They do work for some of large Dominican retailers and have an accountant who speaks conversable English. PM or E-mail me if you will need the name.