"Sette anni ci sono voluti."
How can it be "we have needed" when the verb is "sono" not "siamo?" This is a strange construction.
It's passive. the most natural form in Italian would be "ci sono voluti sette anni", but if you want to put emphasis on the fact that it needed SEVEN years, you can say "Sette anni ci sono voluti". A heavy construction can mean heavy feelings. ;)
Similar re-arranging can be seen in English, for example "Seven years it's taken to put up those flats!".
Fair enough, but that sounds like a good reason to put a whole section on the passive voice. This is the first section on a tense other than present; there's enough to be grappling with as it is!