Bear in mind that you are going to a destination that still has phone booths (orelhao) on every corner to use with the phone cards sold at any of the zillions of kiosks. That should do for any local calls, unless you are so married to your cell you can't conceive of doing without one for a week.
You will also find Internet cafés that facilitate overseas calls, and services such as Skype, in most places tourists frequent.
Hotels/hostels have computers for the use of guests, free.