Castillo del Ambar is a nice little hotel up in the Coca Cola subdivision. Planner is right...there is about 15 rooms with kitchenettes in them. There's a small pool and a pay bar. The muchacho used to be Wilbur (very nice guy....not sure if he is still there or not.)
They usually charge 1000 pesos per night. When you stay for 2 weeks they would drop that to 800 pesos. It ends up working out to about $200 U.S. per week.
I always enjoy staying there. It's close to everything. You can get a tax 809 320-7621 for 150 pesos to the local super mercado Jose Luis.
PM me if you know for sure if you are going and I can give you more info......