NL100 - top set, but ugly turn

[Ramana]

Villain is 50/3 AF: 1.2/1.2/2. I know he has a str8 and I know that he will pay me if I hit my FH. I have around 30% in equity. Is the turn a call?

$0.5/$1 No Limit Holdem
6 players
Converted at weaktight.com

Stacks:
UTG (<font color="#0000cc">$81.48</font>)
UTG+1 (<font color="#0000cc">$80.24</font>)
CO (<font color="#0000cc">$173.44</font>)
Hero (<font color="#0000cc">$104.33</font>)
SB (<font color="#0000cc">$105.10</font>)
BB (<font color="#0000cc">$110.64</font>)

Pre-flop: ($1.5, 6 players) Hero is BTN 5[img]/images/graemlins/club.gif[/img] 5[img]/images/graemlins/spade.gif[/img]
<font color="#777777">2 folds</font>, CO calls $1, <font color="#cc0000">Hero raises to $5</font>, <font color="#777777">1 fold</font>, BB calls $4, CO calls $4

Flop: 3[img]/images/graemlins/spade.gif[/img] 4[img]/images/graemlins/spade.gif[/img] 5[img]/images/graemlins/heart.gif[/img] ($15.5, 3 players)
BB checks, CO checks, <font color="#cc0000">Hero bets $12</font>, <font color="#777777">BB folds</font>, CO calls $12

Turn: 2[img]/images/graemlins/heart.gif[/img] ($39.5, 2 players)
<font color="#cc0000">CO bets $39.5</font>, Hero ???