First and most important, call your agent and let them do all the work for you. It'll save you alot of time and hassle, and the rates will be exactly the same as the cruise line and they charge nothing for their services.
Second, you may have to open your search a bit since the one you want is sold out as there are some options available to you based on what I'm seeing.
Travel Agent/Cruise Specialist w/12 yrs exp and 47 Cruises on 11 cruise lines! Favorites: Paul Gauguin - Tahiti: Uniworld River Cruises - Europe; Celebrity Solstice-class ships; Holland America - 12-nights Baltics & Russia; RCCL - 14-nights Greek Isles, Turkey, & Croatia; Holland America - 14-day Alaskan cruisetour; 10-night Canada/New England cruise; 21 days Hawaii w/7-night NCL cruise; Oceania - 25 days in Asia; more than 3 months touring Europe by train. And many all-inclusive resorts!