The chances of finding ~20 places in a restaurant for NYE in Rome on December 15 should have about 6 zeroes after the comma! The way I see it, unless you want to spend a "nice" evening for two in the hotel (), the only thing I can think of (especially if this is your first time in Rome) get yourself a bag of nice panini and a bottle of some decent wine/prosecco and take a long evening walk through the centro storico and enjoy the night views for a couple of hours or so... Careful, do this with your partner only and forget the other 18 fellow travellers in your group!

...and welcome to FT!