TPGK - Fold to a raise on the river HU?

[Skuzzy]

I'm new to limit so I really havent got a clue beyond what I've read in SSHE. I'm interested in what the best line is to take when your TPGK hand is bet flop, turn and river only to be raised on the river. When is it ight to call, and when is best to fold to the ievitable sucked out two pair?

s this read dependant or more straightforward? A typical example hand, I have no reads at all here having just sat down:

Party Poker 0.5/1 Hold'em (10 handed) converter

Preflop: Hero is SB with Q[img]/images/graemlins/heart.gif[/img], J[img]/images/graemlins/spade.gif[/img].
<font color="#666666">2 folds</font>, UTG+2 calls, <font color="#666666">4 folds</font>, Button calls, Hero completes, BB :#A500AF(Villain)/ checks.

Flop: (4 SB) 8[img]/images/graemlins/club.gif[/img], 3[img]/images/graemlins/club.gif[/img], J[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(4 players)</font>
<font color="#CC3333">Hero bets</font>, Villain calls, UTG+2 folds, Button calls.

Turn: (3.50 BB) T[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(3 players)</font>
<font color="#CC3333">Hero bets</font>, Villain calls, Button calls.

River: (6.50 BB) 4[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(3 players)</font>
<font color="#CC3333">Hero bets</font>, <font color="#CC3333">Villain raises</font>, Button folds, Hero calls.

Final Pot: 10.50 BB

I was thinking on the end he may have been representing the back door flush. Any advice/thoughts?