$55, Rivered second nuts, how much should I bet?

[Patrio]

Reads: Sb has lead the flop out of the sb before and then he had middle pair + straight draw. UTG is limping with all kinds of hands but I think he has a Q or inside + pair here. How much should I bet on river? Comments on all streets appreciated

PokerStars No-Limit Hold'em Tourney, Big Blind is t30 (9 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

BB (t900)
UTG (t4845)
UTG+1 (t2845)
MP1 (t2820)
MP2 (t2775)
MP3 (t2640)
CO (t3115)
Hero (t4120)
SB (t2970)

Preflop: Hero is Button with K[img]/images/graemlins/club.gif[/img], J[img]/images/graemlins/club.gif[/img].
UTG calls t30, <font color="#666666">5 folds</font>, Hero calls t30, SB completes, BB checks.

Flop: (t120) Q[img]/images/graemlins/heart.gif[/img], 9[img]/images/graemlins/spade.gif[/img], 8[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(4 players)</font>
<font color="#CC3333">SB bets t90</font>, BB folds, UTG calls t90, Hero calls t90.

Turn: (t390) 4[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(3 players)</font>
SB checks, UTG checks, Hero checks.

River: (t390) 6[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(3 players)</font>
<font color="#CC3333">SB bets t90</font>, UTG calls t90, <font color="#CC3333">Hero raises to ???

[Lord_Strife]

350