How should I have played this river?

[Helios]

Party Poker No-Limit Hold'em, $ BB (10 handed) converter (http://www.selachian.com/tools/bisonconverter/hhconverter.cgi)

BB ($5.95)
Hero ($42.65)
UTG+1 ($16.5)
UTG+2 ($24.5)
MP1 ($51.8)
MP2 ($28.05)
MP3 ($32.9)
CO ($14.1)
Button ($27.85)
SB ($22)

Preflop: Hero is UTG with 3/images/graemlins/heart.gif, 3/images/graemlins/spade.gif. SB posts a blind of $0.25.
Hero calls $0.50, UTG+1 folds, UTG+2 folds, MP1 folds, MP2 folds, MP3 folds, CO calls $0.50, Button folds, SB (poster) completes, BB checks.

Flop: ($2) 4/images/graemlins/heart.gif, 7/images/graemlins/spade.gif, 2/images/graemlins/club.gif <font color="#0000FF">(4 players)</font>
SB checks, BB checks, Hero checks, CO checks.

Turn: ($2) 3/images/graemlins/club.gif <font color="#0000FF">(4 players)</font>
SB checks, BB checks, <font color="#CC3333">Hero bets $2</font>, CO calls $2, SB folds, BB folds.

River: ($6) T/images/graemlins/club.gif <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $3</font>, CO calls $11.60 (All-In), Hero folds.

Final Pot: $20.60

I had him figured on a draw when I bet the turn. But I bet out anyway what should I have done?

[PoBoy321]

I think you played this hand fine. You were out of position, so you don't want to try to find out if your threes are good on the flop. You hit your set and lead on the turn for a full pot bet. You lead for 1/2 on the river when the flush completes and fold to the push. I think that I would have done exactly the same.