10,flopped set gets raised, what now?

[ottsville]

PokerStars No-Limit Hold'em, $0.10 BB (9 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

MP2 ($15.15)
MP3 ($3.30)
CO ($10)
Button ($9.70)
Hero ($7.10)
BB ($6.05)
UTG ($12.20)
UTG+1 ($9.85)
MP1 ($10.65)

Preflop: Hero is SB with 2[img]/images/graemlins/diamond.gif[/img], 2[img]/images/graemlins/club.gif[/img].
<font color="#666666">2 folds</font>, MP1 calls $0.10, MP2 calls $0.10, <font color="#666666">1 fold</font>, CO calls $0.10, <font color="#666666">1 fold</font>, Hero completes, BB checks.

Flop: ($0.50) 3[img]/images/graemlins/spade.gif[/img], 2[img]/images/graemlins/spade.gif[/img], A[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(5 players)</font>
<font color="#CC3333">Hero bets $0.5</font>, BB folds, MP1 folds, MP2 folds, <font color="#CC3333">CO raises to $1.3</font>, HERO?