I just spent the best part of the afternoon in Cuesta bookshop and there are many Dominican authors to choose from. I didn't know where to start and I'm a little lazy about reading in Spanish. I looked at titles by Angela Hernández, Chiqui Vicioso, Marcio Veloz Maggiolo, Carmen Imbert Brugal, Mu Kien Sang, Pedro Antonio Valdez, and others, including Spanish translations of Julia Alvarez and Junot Díaz.
In summary, lots of fiction, sociology, politics, memoirs, history and poetry. Shelves full of stuff by Bosch and Balaguer, plenty about Trujillo and Porfirio Rubirosa.
There is a new book out about the Hipólito years called (IIRC) 'Anomalía' which looked like a scathing account of the previous president and his administration. The cover photo set the tone - the infamous golden statue of Hippo on horseback.
But if you're not in the DR, here is a great alternative. I'm surprised no one has posted this link:
Dominican Bookshop -The Dominican Republic in Print for a comprehensive selection, and - I hear - excellent service.