Nut flush on a paired board facing strength (50$ NL on Party).

Party Poker No-Limit Hold'em, $ BB (9 handed) FTR converter on zerodivide.cx

Hero ($65.90)
UTG+1 ($42.75)
MP1 ($64.50)
MP2 ($49.95)
MP3 ($14.47)
CO ($39.15)
Button ($63.65)
SB ($46.45)
BB ($49.50)

Preflop: Hero is UTG with J[img]/images/graemlins/heart.gif[/img], A[img]/images/graemlins/heart.gif[/img]. SB posts a blind of $0.25.
<font color="#CC3333">Hero raises to $2</font>, <font color="#666666">5 folds</font>, Button calls $2, <font color="#666666">2 folds</font>.

Flop: ($4.75) K[img]/images/graemlins/club.gif[/img], 7[img]/images/graemlins/heart.gif[/img], K[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $2.5</font>, Button calls $2.50.

Turn: ($9.75) 8[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, <font color="#CC3333">Button bets $6</font>, <font color="#CC3333">Hero raises to $18</font>, <font color="#CC3333">Button raises to $30</font>, Hero ?
River: ($69.75) 3[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>

Final Pot: $69.75

I have no strong read on Vilain but he seems to be neither a maniac nor a rock.
Should I fear the full house and fold or go all in ?
Thank you !