Turn action w/ TPTK

[jsnipes28]

Party Poker No-Limit Hold'em, $1 BB (6 max, 6 handed) converter

Button ($77.35)
SB ($39.15)
BB ($128.35)
Hero ($99)
MP ($59.8)
CO ($58.3)

Preflop: Hero is UTG with A[img]/images/graemlins/heart.gif[/img], K[img]/images/graemlins/spade.gif[/img].
<font color="#CC3333">Hero raises to $4</font>, MP calls $4, <font color="#666666">1 fold</font>, Button calls $4, <font color="#666666">1 fold</font>, BB calls $3.

Flop: ($16.50) 5[img]/images/graemlins/spade.gif[/img], A[img]/images/graemlins/diamond.gif[/img], 8[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(4 players)</font>
BB checks, <font color="#CC3333">Hero bets $10</font>, MP folds, Button calls $10, BB folds.

Turn: ($36.50) 2[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $15</font>, Button calls $15.

River: ($66.50) T[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $25</font>, <font color="#CC3333">Button raises to $48.35 (All-In)</font>, Hero calls $23.35.

Final Pot: $163.20

I underbet the turn thinking pot control so i wouldn't get too carried away w/ TPTK. I also figured that it was enough to extract from a weaker ace as well as get a raise from a 2 pair or set. When he didnt raise the turn i was pretty sure he had a weaker ace. So after he pushed all in i assumed he had hit, but at that point i felt i had to call, or did i?
Suggestions on all streets welcome. What line would you have taken?
Thanks