25NL - always raise this river mindonk? (how much?)

[Prodigy54321]

Full Tilt Poker - No Limit Hold'em Cash Game - $0.10/$0.25 Blinds - 5 Players - (LegoPoker Hand History Converter)

SB: $50.60
BB: $9.00
UTG: $22.50
Hero (CO): $29.50
BTN: $26.85

Preflop: Hero is dealt A[img]/images/graemlins/heart.gif[/img] Q[img]/images/graemlins/diamond.gif[/img] (5 Players)
UTG folds, <font color="red">Hero raises to $1.00</font>, BTN folds, SB calls $0.90, BB folds

Flop: ($2.25) 5[img]/images/graemlins/heart.gif[/img] A[img]/images/graemlins/diamond.gif[/img] 9[img]/images/graemlins/spade.gif[/img] (2 Players)
SB checks, <font color="red">Hero bets $1.50</font>, SB calls $1.50

Turn: ($5.25) 6[img]/images/graemlins/diamond.gif[/img] (2 Players)
SB checks, <font color="red">Hero bets $3.00</font>, SB calls $3.00

River: ($11.25) Q[img]/images/graemlins/spade.gif[/img] (2 Players)
<font color="red">SB bets $0.25</font>, <font color="red">Hero raises to $6.25</font>

villain is 36/1/.46 over about 60 hands

comments on the whole hand are welcome..but I am mainly asking about what to do on this river..

I assume most of you are raising this...if I'm wrong, speak up...

but this mindonk, to me, usually means they are planning on folding to a raise (although I occasionally see a call with high pair, two pair, etc here...and every so often I see a monster from villain and he will be reraising me)...

so what do you think, and based on what villains typically do here, how much would you raise to..I figured I might entice a call if I didn't raise too big, but, then again, I think this raise screams that I'm quite sure I have him beat...it just doesn't really look like a bluff...

thoughts?

BTW, would anyone check this turn and call/bet the river instead?