You would think they could patch the gash in the hull as part of this. Then once you rolled it enough where the open areas were out of the water you could just pump the water out...
I can't imagine how big the "platform" is going to need to be in order to keep the ship from sliding off into deep water. It would be a very interesting problem from an engineering perspective.
The next question is, How much is it going to cost to put her back into service. I imagine the engines are going to need to be replaced at the very least maybe most of the internal systems at this point...
Carnival Cruise Lines:
Fantasy 90, Celebration 95, Victory 05, Conquest 05, Spirit 6/06, Freedom 6/08, Holiday 7/08, Victory 6/09, Valor 9/09, Dream 6/10, Splendor 8/10,Conquest 8/11,Magic 11/11,Triumph 4/12,Spirit 7/12,Freedom 11/12, Triumph 2/13 - The fire cruise
NCL Dream October 2006, RCCL Mariner OTS June 2007