I would have re-raised on the flop. With top pair top kicker increase the money in the pot. If everyone folds thats fine.

I would put SB on a top pair weaker kicker. I wouldn't worry about him having a straight draw. If he has bottom pair with four to the heart flush, say Q5 [img]/images/graemlins/heart.gif[/img] then your 50/50.

I would have also bet the river. If he bet three clubs on after the flop and then beats you runner runner what can you do.