Go to Laguna (30 km from Ibiraquera), and take the ferry to cross your car, it would only take you 5 min usually, but during summer there's a lot of traffic (especially during weekends) and you could be stuck there for half an hour.
Since there it's quite simple, just follow the sings until you reach the lighthouse.
You can perfectly make it with a small car, but I recomend you a 4x4
It's good when at Ibiraquera the wind is a little bit too much from the east, here you could found better conditions or at least less crowd and it's a fun day trip to make.
