As Oliver stated, it will say on the box and rules 2nd Edition.
Since you seem to have 1st Edition, I would print out the 2nd Edition rules. It only changes a few things so you don't have to make significant changes to your game. I believe all you'll have to do is remove the French Bateux from the starting deck. I have the rules, but I'm lazy...
Anyway, yeah, use the 2nd Ed rules. And enjoy the game - it's tons o' fun!
And the specific rules changes between the 1st and 2nd edition are listed right on the front page of the 2nd Ed. rules, so you don't have to read two sets of rules and try to figure out what the changes are.