Hiring a car for you stay in Corsica is highly recommended as the public transport and taxi service is not reliable. Here are instructions on how to reach the Villa:

Leave Figari airport (there is only one road) and continue a couple of kilometers to the T juntion with the D859.
Turn left to Porto Vecchio.
Continue on this road, through the villages of Figari and Sotta, there is a fixed speed camera after about 16.5k
At the roundabout with a stone arch in the centre (the junction with the N198 to Bonafacio), take the second exit signed Palombaggia. There is a boat shop at this exit.
The distance to this point is about 18k.
Proceed along this road, passing through the tiny hamlet of Piccovajio.
Another couple of kilometers, then fork right, (the left fork takes you down to the beach with lots of parking and excellent cafe)
Continue past a grocery store on the right (where you can buy just about everything)
Shortly after this you come to a sharp left hand bend, and there is a large sign to U.Latonu and Belvedere.
Turn slightly right and immediately left into a private road with stone wall and gate.
The villa is the first turn on the left down a very steep slope, then bear left.
The distance from the N198 roundabout to the villa is approximately 11k.