TPTK: river call +EV ? Raise turn?

[Wardfish]

Prima 50/$1, 6max, 6handed

Folded to me (230) in CO, i standard open to 3 with A [img]/images/graemlins/spade.gif[/img] Q [img]/images/graemlins/heart.gif[/img], called by button (57 remaining) & SB(91 rem). Pot $10

Flop A [img]/images/graemlins/diamond.gif[/img] K [img]/images/graemlins/spade.gif[/img] 4 [img]/images/graemlins/diamond.gif[/img]
I lead for 7, button folds, SB raises to 21.

I think for a while and eventually call, as the SB has been bemoaning his bad luck recently: he hasnt won many hands despite being involved in quite a few. Pot $52

Plan here is to keep the pot fairly small, although i believe i probably have the best hand.

Turn 6 [img]/images/graemlins/spade.gif[/img]

SB bets out 7, i call. Pot $66

River 8 [img]/images/graemlins/club.gif[/img]

SB goes all-in for $64


My questions are:

how much EV in calling ?
better to raise the turn ?
should i trust my initial read and call ?