Should I bluff the river here?

[AceofSpades]

Full Tilt Poker, NL Hold'em Tournament, 2,500/5,000 Blinds, 600 Ante, 6 Players
LegoPoker Hand History Converter

SB: 106,260
BB: 62,490
UTG: 345,564
Hero (MP): 106,641
CO: 314,914
BTN: 196,460

Pre-Flop: (11,100) T[img]/images/graemlins/diamond.gif[/img] 9[img]/images/graemlins/club.gif[/img] dealt to Hero (MP)
UTG folds, <font color="red">Hero raises to 11,100</font>, CO calls 11,100, 3 folds

Flop: (33,300) 4[img]/images/graemlins/diamond.gif[/img] Q[img]/images/graemlins/club.gif[/img] K[img]/images/graemlins/club.gif[/img] (2 Players)
<font color="red">Hero bets 15,000</font>, CO calls 15,000

Turn: (63,300) 8[img]/images/graemlins/spade.gif[/img] (2 Players)
Hero checks, CO checks

River: (63,300) 5[img]/images/graemlins/spade.gif[/img] (2 Players)
Hero ?