For a VERY crude solution

Take the Normally closed line to +5. Take the Normally open line to 0v. Put a resistor of about 4.7k from the switch common to +5 v and take another connection form common to the INT pin.

It really could do with better buffering and filtering than that, but it will get you going. Don't be too suprised when you get multiple triggers though. A debounce circuit can be built with a hex schmitt trigger and a couple of R and C

Steve