New Years Eve is like the biggest day for tourists here in Las Vegas. As a result room rates are sky high and I would assume so will be airplane ticket prices. Simply by changing you arrival day to a day or two earlier would most likely save you a lot of money.
So if you can change your travel dates I'm betting you could save a lot by not arriving on the busiest day of the year in Vegas.
Book you room early and any shows you plan to attend.