What about restaurants, shopping, holiday sport activities, ATMs etc? Rest assured: the Portisco Marina is popular with big yacht owners, so you'll find those shops etc nearby.

6.5 km from Portisco: the village San Pantaleo. A few km further off: the popular (and expensive) resorts Porto Cervo and Porto Rotondo.

Swim and play at the famous Rena Bianca beach.

Vacation sports available here/nearby: Tennis, Golf, Biking, Fishing, Boating, Snorkeling/Diving, Surfing ...
or rent deck chairs, beach umbrellas if you prefer the quiet beach life ... horse riding: available a little further off.

Portisco has a couple of hotels, but the best way to live here (unless you have a yacht) is to rent a small apartment; at reasonable prices in the low seasons:
May..mid-June,
mid-September..October.
The people who own these flats are multi-lingual: French, English, Italian,.....