AKo on the button facing shorter stacked in co

[nuclear500]

Down to 10 players of about 100 starting. This is a free tournament that is run in Madison, WI (www.badgerpoker.com) but once it gets down to the final 20 (ITM as I call it, you get points) it is for the most part all "real" players, an occasional suck-out artist makes it there by pure luck cracking multiple huge hands with weak cards - but they usually don't last long, the blinds are killer due to needing to get the tournament done.

You're holding A [img]/images/graemlins/heart.gif[/img] K [img]/images/graemlins/spade.gif[/img] on the button. A tight player is folded to in the cutoff and makes it 4.5xBB, leaving him with 4.5BB left. You have about 18BB. This player has only shown down strong hands since you joined the table, he has only shown AK, AA and TPBK (QJs) since you sat down.

Two questions:
1. Your move?
2. If you call and SB and BB fold and the board reads 542r and shorter stack puts his remaining 4.5BB in, whats your move? You believe you're drawing to the wheel or your A or K only. Pot is now at 15BB, calling is getting you about 3.25:1