Line with top 2 pair against suspected set

[silly_monkey]

Villan is TAG with 19/11/2.3 stats.

I think I'm up against either a set or random two pair on the flop.

What is the standard line here?

Paradise Poker 2/4 Hold'em (7 handed) FTR converter on zerodivide.cx

Preflop: Hero is Button with A[img]/images/graemlins/heart.gif[/img], K[img]/images/graemlins/spade.gif[/img]. CO posts a blind of $3.
<font color="#666666">3 folds</font>, CO (poster) checks, <font color="#CC3333">Hero raises</font>, <font color="#666666">1 fold</font>, BB calls, CO calls.

Flop: (7 SB) A[img]/images/graemlins/club.gif[/img], K[img]/images/graemlins/heart.gif[/img], 3[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(3 players)</font>
BB checks, CO checks, <font color="#CC3333">Hero bets</font>, <font color="#CC3333">BB raises</font>, CO folds, <font color="#CC3333">Hero 3-bets</font>, <font color="#CC3333">BB caps</font>, Hero calls.

Turn: (7.50 BB) 8[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">BB bets</font>, Hero calls.

River: (9.50 BB) 4[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">BB bets</font>, Hero calls.

Final Pot: 11.50 BB