Bottom 2 pair on wet board

[KEW]

First hand at table so no reads on villian..Opinions on all streets please as I felt completly lost..Villian had not played any hands before I posted BB..THe hand ranges I had him on based on limited table observation was FD,better two pair(56s),set or small over pair(77-99)..After his turn bet I discounted the FD from his range..

Party Poker No-Limit Hold'em, $ Hero (8 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

UTG+1 ($98.50)
MP1 ($54.43)
MP2 ($145.72)
CO ($17.10)
Button ($99.29)
SB ($87.36)
Hero ($100)
UTG ($143.71)

Preflop: Hero is BB with 5[img]/images/graemlins/diamond.gif[/img], 4[img]/images/graemlins/diamond.gif[/img]. SB posts a blind of $0.50.
<font color="#666666">2 folds</font>, MP1 calls $1, <font color="#666666">2 folds</font>, Button calls $1, SB (poster) completes, Hero checks.

Flop: ($4) 5[img]/images/graemlins/club.gif[/img], 6[img]/images/graemlins/heart.gif[/img], 4[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(4 players)</font>
SB checks, <font color="#CC3333">Hero bets $4</font>, <font color="#CC3333">MP1 raises to $8</font>, Button calls $8, SB folds, Hero calls $4.

Turn: ($28) J[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(3 players)</font>
Hero checks, <font color="#CC3333">MP1 bets $15</font>, Button calls $15, Hero calls $15.

River: ($73) 8[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(3 players)</font>
Hero checks, MP1 bets $30.43 and is all in, Button folds, Hero ?????
Final Pot: $73