Unfortunately, the Olive Garden TV ad was only instrumental, no words. And I haven't found an Olive Garden site on the web (I had thought of asking their Advertising Agent if they had a particular source for the music).
Haven't had time to search in detail, but here are a couple of promising-looking sites obtained with a Dogpile Search for Italian + Music:
"The Italian Music Homepage" - a list of links - at http://www.cilea.it/music/entrance.htm
"Italian music composers & composition: Various information on the Web" - another list of links at http://www.cilea.it/music/muscompo.htm#libretti
Let me know if you find it, I'd like the lyrics too!
BTW, "curiously enough", the Bank of Montreal's version of The Times They are A-Changing (which did include lyrics) left out key lines like - "The battle outside is raging" ... "We'll soon shake your windows and rattle your walls" ... and "Your sons and your daughters are beyond your command" ... (leaving a much manicured song that fitted better with their corporate image...)