How about the Palma Bonita - Las Terrenas? A new (completed in Nov. 2000) bungalow with two apartments, each fully furnished, with kitchen/gas stove/fridge, living room, bedroom, bathroom/shower, 24-hour-water/power supply, terrace, parking facilities etc. within a five-minute-walk distance from the Playa Bonita, US$170 per week. Further details on http://home.sunrise.ch/jluksik/ -Admittedly this bungalow belongs to me. To be fair also check out the other options: www.the-samana-page.com/ - I'm sure you'll find something suitable.
Have a nice vacation in my country, Celanda.