AK - Two Pair on Turn - Extracting the most chips

[El Maximo]

Im looking to improve my post flop play. I make 1/2 pot size bet on the flop. This is a typical value bet for me when the board is not scary. How do I extract the most from villian when I hit my 2 pair on the turn? I was thinking of making a 1/3 to 1/2 pot size bet again or check-raising. This is at a 20+2 SnG. Villian has played typically so far. Not a maniac but not a rock either. The only hand Ive shown so far is AK.

Party Poker No-Limit Hold'em Tourney, Big Blind is t15 (9 handed) converter

MP1 (t865)
MP2 (t1580)
MP3 (t840)
CO (t795)
Button (t670)
Hero (t935)
BB (t735)
UTG (t1125)
UTG+1 (t455)

Preflop: Hero is SB with K[img]/images/graemlins/heart.gif[/img], A[img]/images/graemlins/club.gif[/img].
<font color="#666666">1 fold</font>, UTG+1 calls t15, <font color="#666666">3 folds</font>, CO calls t15, <font color="#666666">1 fold</font>, <font color="#CC3333">Hero raises to t90</font>, BB calls t75, UTG+1 folds, CO folds.

Flop: (t210) 4[img]/images/graemlins/spade.gif[/img], 5[img]/images/graemlins/diamond.gif[/img], K[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets t125</font>, BB calls t125.

Turn: (t460) A[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero ??