TPNK, river decision?

Party Poker 5.00/10.00 Hold'em <font color="#0000FF">(10 handed)</font> link

MP3 is 18.89/8 af 2.09 after 1900 hands, TAGish
SB is 45.22/6.09 af 1.18 after 115 hands

Preflop: Hero is BB with K[img]/images/graemlins/spade.gif[/img], 6[img]/images/graemlins/diamond.gif[/img].
<font color="#666666">3 folds</font>, MP3 calls, <font color="#666666">2 folds</font>, SB completes, Hero checks.

Flop: (3.00 SB) K[img]/images/graemlins/heart.gif[/img], 5[img]/images/graemlins/spade.gif[/img], Q[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(3 players)</font>
<font color="#CC3333">SB bets</font>, <font color="#CC3333">Hero raises</font>, MP3 calls, SB calls.

Turn: (4.50 BB) 7[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(3 players)</font>
SB checks, <font color="#CC3333">Hero bets</font>, MP3 calls, SB calls.

River: (7.50 BB) 9[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(3 players)</font>
SB checks, Hero checks, <font color="#CC3333">MP3 bets</font>, SB folds, Hero?

What do i possibly beat here? is the pot too big to fold in this spot?