How terrible! I can't believe that hike in prices, especially when so many places in Hawaii are having such trouble right now.
I don't know if you have flexibility on time, but I always thought it would be cool to have a brunch reception - you could drink mimosas, have breakfast foods and perhaps save some money. Of course, that means moving your ceremony up, but it may mean you're able to keep the costs down a little.
Good luck! It'll all work out.