Flopped nut flush - help me extract the most

[Kost]

Full Tilt Poker - No Limit Hold'em Cash Game - $0.50/$1 Blinds - 6 Players - (LegoPoker HH Converter)

<font color="black">Hero (SB): $99.00</font>
BB: $305.00
UTG: $79.90
MP: $223.85
CO: $101.65
BTN: $289.00

<font color="black">Preflop:</font> Hero is dealt 8[img]/images/graemlins/spade.gif[/img] K[img]/images/graemlins/spade.gif[/img] (6 Players)
3 folds, BTN calls $1.00, Hero calls $0.50, BB checks

<font color="black">Flop:</font> ($3) 3[img]/images/graemlins/spade.gif[/img] 2[img]/images/graemlins/spade.gif[/img] A[img]/images/graemlins/spade.gif[/img] (3 Players)
Hero checks, BB checks, <font color="red">BTN bets $3.00</font>, Hero calls $3.00, BB calls $3.00

<font color="black">Turn:</font> ($12) 8[img]/images/graemlins/club.gif[/img] (3 Players)
Hero checks, BB checks, <font color="red">BTN bets $7.00</font>, Hero calls $7.00, <font color="red">BB raises to $28.00</font>, BTN folds, <font color="red">Hero?

BB is 24/13/0.7