Gabriela, I would question, if you are lost now, with all the web's information at your fingertips (maps etc), then how will you manage when you are on the road driving in Italy? I say this, not meaning to be rude, but to offer guidance.
Personally, I wouldn't take a car to Sorrento. Drop it back in Tuscany/Umbria and catch the train to Naples/Salerno.
I think it is also helpful for the experts on this Forum to see your trip as a whole rather than many individual posts
Is this the trip you are you planning ?
Venice > Verona > Milan > Cinque Terre > Florence > Tuscany & Umbria > Sorrento & Amalfi Coast