set vs unknown raiser nl100

he is new to the table, pt stats 35/13/1.5, no reads

Party Poker No-Limit Hold'em, $ BB (6 max, 6 handed) converter

Hero ($101.35)
Button ($105.40)
SB ($230.92)
BB ($25)
UTG ($102.45)
MP ($137.49)

Preflop: Hero is CO with 6[img]/images/graemlins/diamond.gif[/img], 6[img]/images/graemlins/club.gif[/img]. SB posts a blind of $0.50.
UTG calls $1, <font color="#666666">1 fold</font>, Hero calls $1, <font color="#CC3333">Button raises to $4</font>, <font color="#666666">1 fold</font>, BB calls $3, UTG calls $3, Hero calls $3.

Flop: ($16.50) 6[img]/images/graemlins/heart.gif[/img], K[img]/images/graemlins/diamond.gif[/img], Q[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(4 players)</font>
BB checks, UTG checks, Hero checks, <font color="#CC3333">Button bets $6</font>, BB folds, UTG folds, <font color="#CC3333">Hero raises to $20</font>, Button calls $14.

Turn: ($56.50) 2[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $30</font>, Button calls $30.

River: ($116.50) T[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
Hero ?????