TPTK, am I missing value here?

[Sledgejammer]

Villains line confused me so much here I just called, am I loseing value here or does a raise only get called by a better hand? Does Villain sometimes have a fishy played monster, or should I be jamming it in on the river? Also, the turn, should I be raising here also?

My thinking here is anything from air to a slow played flopped set to a flush draw (I often see them bet this way, usually followed by a much larger river bet, though), to ace-ten which then made aces up...

Party Poker - No Limit Hold'em Cash Game - $0.10/$0.25 Blinds - 5 Players - (LegoPoker Hand History Converter)

SB: $21.32
BB: $33.54
UTG: $27.17
CO: $27.80
Hero (BTN): $26.29

Preflop: Hero is dealt K[img]/images/graemlins/spade.gif[/img] A[img]/images/graemlins/diamond.gif[/img] (5 Players)
<font color="red">UTG raises to $1.00</font>, CO folds, <font color="red">Hero raises to $4.00</font>, SB calls $3.90, 2 folds

Flop: ($9.25) T[img]/images/graemlins/spade.gif[/img] 7[img]/images/graemlins/spade.gif[/img] 5[img]/images/graemlins/heart.gif[/img] (2 Players)
<font color="red">SB bets $0.75</font>, <font color="red">Hero raises to $4.00</font>, SB calls $3.25

Turn: ($17.25) A[img]/images/graemlins/heart.gif[/img] (2 Players)
<font color="red">SB bets $1.25</font>, Hero calls $1.25

River: ($19.75) 9[img]/images/graemlins/spade.gif[/img] (2 Players)
<font color="red">SB bets $0.75</font>, Hero calls $0.75

Pot Size: $21.25 ($1.06 Rake)