Very passive player donk the river... Plan = ?

[Mig]

I'm really tempted to raise but a 0.2 overall (0.1 on the river) is donking the river..

Party Poker 10/20 Hold'em (6 max, 6 handed) http://216.119.70.224/converter/hhconverter.pl

Preflop: Hero is UTG with J[img]/images/graemlins/spade.gif[/img], K[img]/images/graemlins/club.gif[/img].
<font color="#CC3333">Hero raises</font>, <font color="#666666">3 folds</font>, SB calls, <font color="#666666">1 fold</font>.

Flop: (5 SB) 6[img]/images/graemlins/diamond.gif[/img], 6[img]/images/graemlins/spade.gif[/img], K[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
SB checks, <font color="#CC3333">Hero bets</font>, SB calls.

Turn: (3.50 BB) 3[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
SB checks, <font color="#CC3333">Hero bets</font>, SB calls.

River: (5.50 BB) 3[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">SB bets</font>, Hero ???