Top2 with flush out....how much to bet on the turn?

[NYTyler]

What's my line here on the turn? I believe a bet is most appropriate here about 400-500? I find situations like this common and hate to dump chips to a better hand but hate it even more when the 4th [img]/images/graemlins/diamond.gif[/img] comes off and I loose to 7x7 [img]/images/graemlins/diamond.gif[/img].

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

UTG (t1055)
UTG+1 (t2840)
MP1 (t1340)
MP2 (t1550)
Hero (t1790)
CO (t1210)
Button (t2930)
SB (t1485)
BB (t3150)

Preflop: Hero is MP3 with Q[img]/images/graemlins/heart.gif[/img], A[img]/images/graemlins/heart.gif[/img].
<font color="#666666">3 folds</font>, MP2 calls t30, <font color="#CC3333">Hero raises to t135</font>, <font color="#666666">2 folds</font>, SB calls t120, BB calls t105, MP2 folds.

Flop: (t435) Q[img]/images/graemlins/diamond.gif[/img], 2[img]/images/graemlins/spade.gif[/img], 2[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(3 players)</font>
SB checks, BB checks, <font color="#CC3333">Hero bets t210</font>, SB calls t210, BB folds.

Turn: (t855) A[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
SB checks, Hero?