I know Im beat on the turn, but what do i do on the river

[Sightless]

SB plays over 60%of his hands, and raises about 3% of hands preflop, postflop he seems decent, and has AF 1.4

When he c/r me on the turn i knew I was behind, but figured I was probably good enough to continue... What does Hero do at the river?Raise, Call?Fold?
Party Poker 0.50/1 Hold'em (6 max, 5 handed) FTR converter on zerodivide.cx

Preflop: Hero is UTG with A[img]/images/graemlins/spade.gif[/img], 9[img]/images/graemlins/diamond.gif[/img].
<font color="#CC3333">Hero raises</font>, <font color="#666666">2 folds</font>, SB calls, <font color="#666666">1 fold</font>.

Flop: (5 SB) A[img]/images/graemlins/heart.gif[/img], 7[img]/images/graemlins/club.gif[/img], T[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
SB checks, <font color="#CC3333">Hero bets</font>, SB calls.

Turn: (3.50 BB) Q[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
SB checks, <font color="#CC3333">Hero bets</font>, <font color="#CC3333">SB raises</font>, Hero calls.

River: (7.50 BB) 7[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">SB bets</font>, <font color="orange"> Hero? </font>