AK flops top two in interesting position

[cowboy.up]

Villain is 18/12 and had 3 bet twice before causing me to fold, so my thoughts are that he could be making a play at me again.

PokerStars No-Limit Hold'em, $0.50 BB (6 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

UTG ($15.45)
MP ($29.75)
CO ($132.10)
Hero ($63.45)
SB ($56.10)
BB ($49.25)

Preflop: Hero is Button with K[img]/images/graemlins/club.gif[/img], A[img]/images/graemlins/heart.gif[/img].
UTG calls $0.50, <font color="#666666">1 fold</font>, <font color="#CC3333">CO raises to $2.5</font>, <font color="#CC3333">Hero raises to $7.5</font>, <font color="#666666">2 folds</font>, UTG folds, <font color="#CC3333">CO raises to $18</font>, Hero calls $10.50.

Flop: ($37.25) A[img]/images/graemlins/spade.gif[/img], K[img]/images/graemlins/heart.gif[/img], Q[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">CO bets $24.5</font>, Hero...?

Should I have dropped the hand preflop?...and once I flop top two and he shows aggression I think our only moves are folding or pushing because a call would leave about 70 in the pot with 20 back that would have to go in no matter the turn.

Thoughts?