2pair becomes 1card T-high flush, river decision problem (6max)

[unzip]

Loosepassive table, no special reads on villains.
Please suggest/explain best river line. I was quite lost once As hit.

PokerStars $0.05/$0.10 Limit Hold'em - 6 players
Hand Converter Tool from DeucesCracked.com

Preflop: Hero is BB with 8[img]/images/graemlins/heart.gif[/img], T[img]/images/graemlins/spade.gif[/img]
UTG folds, MP calls, CO calls, Button calls, SB calls, Hero checks.

Flop: (5.00 SB) T[img]/images/graemlins/club.gif[/img], 8[img]/images/graemlins/spade.gif[/img], 4[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(5 players)</font>
SB checks, <font color="#FF0000">Hero bets</font>, MP calls, CO calls, Button calls, SB folds.

Turn: (4.50 BB) 3[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(4 players)</font>
<font color="#FF0000">Hero bets</font>, MP calls, CO calls, Button calls.

River: (8.50 BB) A[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(4 players)</font>
<font color="#FF0000">Hero bets</font>, MP folds, CO calls, <font color="#FF0000">Button raises</font>, Hero ??