100NL - big flush draw turn action

[NNH]

PokerStars No-Limit Hold'em, $1.00 BB (6 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

BB ($190.90)
UTG ($27.20)
MP ($94.50)
CO ($69.50)
Hero ($121.45)</font>[/b]
SB ($109.45)</font>[/b]

Preflop: Hero is Button with A, 2.
3 folds</font>, Hero raises to $4</font>, SB calls $3.50, 1 fold</font>.

Flop: ($9) 6, 7, 4 (2 players)</font>
SB checks, Hero bets $6</font>, SB raises to $16</font>, Hero calls $10.

Turn: ($41) 9 (2 players)</font>
SB bets $19</font>, Hero ?

Villain in this hand has been pretty tight PF and has been folding to aggression postflop alot.

How's my play on the flop, and what should I do on the turn?