Congrats !!! My DW and I just came back from a cruise this past week on the Carnival Legend. Played the last game of BINGO on the last evening of the cruise, and we won.B-I-N-G-O !!! a Free cruise for 2 for 3, 4, 5, 6, or up to a 7 nite cruise, with a category 6A stateroom as well.
The certificate I received on Board (formal certificate to arrive within 3 weeks) listed the following exclusions*: No Xmas or New Years cruises, must be used within 12 months of original sailing date of the cruise we were on, non-transferrable and No Cash Value.
Any airfare, port taxes and fees, as well as IRS responsibility for the value of the cruise selected is on us. I have some of the same questions u have, including possible upgrading. We already have booked a cruise for next June, and have time-share plans for Xmas & New Years; just have to find a time slot to go 
Post a comment when you receive that info, and I will do the same