1995 Saturn SL2, 196759 mileage

I have a 1995 Saturn SL2 with 196759 miles. I was told a few months ago that the catalytic converter was going bad, but that I could wait until I planned to replace the car (one year) and it would be fine.

Since then my car began sputtering (almost dying). Once (after sputtering and almost dying) the engine light came on (solid) and remained on until I reached my destination.

That was about a week ago. Since then I have only driven the car short distances and it was doing fine, until last night when it died without warning. It started up right away, and I got it home.

Other sidenote, there is oil in at least one of my spark plug cylinders and I was burning oil, at least one quart every 300 miles.

I really can't afford a new car just yet.

Questions:

Could a catalytic converter cause the engine light to come on, and the car to sputter and die?

Is the engine light code stored in the car's computer even though the engine light is no longer lit?

Since the catalytic converter has been bad for a while, how much potential damage could this have caused to other areas of the car, in other words after I replaced the catalytic converter am I just going to have to replace a bunch of other parts since I was misinformed and waited so long?

What else could cause these kinds of problems?

Thank you so much.