Basic Hold'em Question

[amtannn]

Hi, all. I'm a recreational player looking to have some fun and hopefully improve so I started playing no limit tournaments. I'm sure that this is pretty basic, and probably written in a book somewhere, but yesterday I was playing in a no limit tournament and I made a play I'm not sure was correct.

I came in for $50 on the button with a Q10. Small blind calls and Big blind lets it run. Flop comes KJ7. Small blind checks, big blind checks, middle limper calls, I bet $200. Small blind calls, big blind re-raises all in for $600. Middle limper folds. I've got about $1,500 in chips and I call, small blind calls as well. Turn comes 4. Small blind checks, and I bet $200. Small blind folds. River comes 2. Big blind turns over his cards and has a K7. I lose to two pair.

My question is if I thought he had two pair or trips, which was what I thought he had, was I dumb to call his all in bet? Is an open ended straight worth calling against a two pair? I know that I have 8 outs, and can calculate whether it makes sense given the size of the pot. But how do you calculate the fact that he has 4 cards that can beat my straight? Where can I learn this kind of basic info?