AKo with a big stack

[mrface]

Playing a $50 NL Hold 'em MTT on party. Had worked my way up from 2x the BB at 100/200 blinds to now have a relatively large stack of ~13000 at 300/600 blinds. 92 people left, top 80 pay. Now that I have a decent stack, I'm looking to finish high -- not just finish in the money.

Villain in this hand is 2 seats to my left and relatively unknown. He has only been on the table for short time and hasn't been involved in many pots (he open-raised with what he said was AK, and folded to BB push when flop came Qxx). He has also seen me steal a few times and push in without callers a couple times before I made a big stack. Also, he has me covered by about 3000.

I get AKo 4 off button, folded to me and I make it 1500, my standard raise at these blinds. He raises to 4500 from CO, and it's folded back to me. What's my move?