"She comes from the restaurant."
Translation:Lei viene dal ristorante.
Not all words require an article :) For instance most cities, e.g. "Viene da Roma", some countries, e.g. "Viene da Cuba", or some idiomatic situations, e.g. "Viene da casa", "Viene da destra". There is also the case with people's names, but in that case it doesn't mean from and I shouldn't spoil too much :)
As far as I know, you don't. In the excersize I had before the multiple choice, which was translate the italian Viene Dal Ristorante into English, the excersize seemed to accept It comes from the restaurant, as well as she (and I'm lucky as I was worried I'd have to report that as a flaw again).