catalytic converter and rim spacing measurements

I have a 96 GA SE. My engine light came on and I had it read. It listed my catalytic converter as being messed up. Seeing as I have 190k miles on my car I was looking for a new one. What is the diameter of the Catalytic converter on my car. And also what are the lug patterns that I would need to know when purchasing Rims for my car.

Thank You,
Daniel