Ace High Flush, Paired Board, River Action?

[carniplant]

Reads: SB loose passive
MP Loose, average agg

Party Poker 2/4 Hold'em (9 handed) converter

Preflop: Hero is BB with A[img]/images/graemlins/diamond.gif[/img], J[img]/images/graemlins/diamond.gif[/img].
UTG folds, UTG+1 folds, MP1 calls, MP2 folds, MP3 folds, CO calls, Button calls, SB completes, <font color="#CC3333">Hero raises</font>, MP1 calls, CO folds, Button calls, SB calls.

Flop: (9 SB) T[img]/images/graemlins/diamond.gif[/img], 8[img]/images/graemlins/club.gif[/img], 6[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(4 players)</font>
SB checks, Hero checks, MP1 checks, Button checks.

Turn: (4.50 BB) 6[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(4 players)</font>
SB checks, <font color="#CC3333">Hero bets</font>, MP1 calls, Button folds, SB calls.

River: (7.50 BB) 7[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(3 players)</font>
<font color="#CC3333">SB bets</font>, <font color="#CC3333">Hero raises</font>, <font color="#CC3333">MP1 3-bets</font>, <font color="#CC3333">SB caps</font>, Hero ???

I'm calling MP's 3bet without hesitation but when i comes back 2 cold to me on the river i feel like loosing my lunch(passive sb's lead-cap on that board felt bad)whats my river play?