AK 3-bet

[pegger]

First hand at table against unknown in CO.

PokerStars No-Limit Hold'em, $0.50 BB (6 handed) internettexasholdem.com

Hero ($50)
UTG ($63.65)
MP ($33.40)
CO ($170.90)
Button ($23.75)
SB ($20.10)

Preflop: Hero is BB with K[img]/images/graemlins/heart.gif[/img], A[img]/images/graemlins/club.gif[/img].
<font color="#666666">2 folds</font>, <font color="#CC3333">CO raises to $2</font>, <font color="#666666">2 folds</font>, <font color="#CC3333">Hero raises to $7</font>, CO calls $5.

Flop: ($14.25) K[img]/images/graemlins/diamond.gif[/img], 2[img]/images/graemlins/heart.gif[/img], 3[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $10</font>, <font color="#CC3333">CO raises to $56.5</font> Hero??

I just read PNL and with a SPR of 3.2 I thought I should be committed on the flop. Also, is preflop alright or should I make in more b/c I'm out of position.