Aeropostal (a Venezuelan airline) flies from Santo Domingo to to S. America using Caracas as the hub. My girlfriend's round trip ticket to Ecuador is $495.
Copa also flies to S. American through Panama.
The website that I found for DR/S. America flights is www.abstravel.com.
Does anyone know of any other travelocity type websites that specialize in Latin America (ie not using connecting flights in the US).