Weird line from villain

Here's a hand that's been bugging me all day. Main villain seems at least half-decent, although I don't have enough hands on him to be sure. UTG in this hands is incredibly loose and BB are pretty much unknown.

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

SB ($9.25)
BB ($96.80)
UTG ($68.10)
MP ($106.35)
CO ($98.05)
Hero ($262.23)

Preflop: Hero is Button with 5[img]/images/graemlins/diamond.gif[/img], 7[img]/images/graemlins/diamond.gif[/img]. SB posts a blind of $0.50.
UTG calls $1, <font color="#CC3333">MP raises to $3</font>, <font color="#666666">1 fold</font>, Hero calls $3, <font color="#666666">1 fold</font>, BB calls $2, UTG calls $2.

Flop: ($12.50) 5[img]/images/graemlins/club.gif[/img], A[img]/images/graemlins/diamond.gif[/img], 7[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(4 players)</font>
BB checks, UTG checks, MP checks, <font color="#CC3333">Hero bets $9</font>, BB folds, UTG folds, MP calls $9.

Turn: ($30.50) 2[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">MP bets $25</font>, Hero...

What's my plan for the rest of the hand?

Dumle

[Hattifnatt]

Call and fold if he makes a big bet on the river unless you fill or hit your flush.