Top pair weak kicker facing raise on river

[garethc]

I wasn't too sure about how to play this hand at any point. If anyone can give advice or criticism on any street it would be appreciated.
Villain has been at the table for a while and hasn't done anything crazy. Hero has been playing very TAG.


Full Tilt No-Limit Hold'em, $0.50 BB (8 handed) Full Tilt Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

MP2 ($25.35)
CO ($42.15)
Button ($9.95)
SB ($49.25)
Hero ($51.55)
UTG ($40.20)
UTG+1 ($13.65)
MP1 ($50.90)

Preflop: Hero is BB with J[img]/images/graemlins/diamond.gif[/img], 9[img]/images/graemlins/club.gif[/img].
UTG calls $0.50, <font color="#666666">3 folds</font>, CO calls $0.50, Button calls $0.50, SB completes, Hero checks.

Flop: ($2.50) 6[img]/images/graemlins/spade.gif[/img], 9[img]/images/graemlins/spade.gif[/img], 7[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(5 players)</font>
SB checks, <font color="#CC3333">Hero bets $2.5</font>, UTG calls $2.50, CO folds, Button folds, SB folds.

Turn: ($7.50) 3[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $5.25</font>, UTG calls $5.25.

River: ($18) 8[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $7</font>, <font color="#CC3333">UTG raises to $25.5</font>, Hero ???