I assume that the
on the flop is actually a
and that the
is actually a
....
Anyway, I don't like the hand; I can't imagine that you are a moneyfavorite here. Even if a decent player flat calls on this board you have to take the possibility into account that he has the nut straight but wants to see a safe turn card first. The preflop raiser cold calling the raise means that he either has a big wrap 8-J and waits for the turn to become aggressive, or AAxx with the nut flush draw. I'm not sure about the SB, but I bet that right now he has a better hand than you. I think your only hope is that your flush draw is good (or that you hit one of your miracle outs). So, unless I have a very strong read that SB is making a play because he thinks everyone is weak, I'd fold.
Even though the hand looks very nice on the flop, you have to figure that a) a raise will put you in a difficult position for all your chips, where you could be drawing totally dead, and that b) even if you just get one caller, there may be many turncards that can make your life difficult: any flush card leaves you guessing, and a 9 or a T might give someone a higher straight. You also don't want to see the board pair up of course.
In short, both players show considerable strength and interest in the pot. You don't have the nuts and you only have two nut outs, so fold.
I don't know which levels you normally play, but the problem for me would be that I don't know very well how the people there play and how tricky they are. I think that you can only decide to buy in short if you know pretty well what the texture of the game will be like. If you are in unfamiliar territory you are always guessing whether your opponents are testing you, trying to outplay you, or really have you beat.
What was the outcome? Where was this game by the way?
Pieter