Should I have old or new parts put in?

Hi, I have a 1992 Saturn I bought used a month or so ago with 76,000 miles. After replacing the catalytic converter it ran great, passed smog no problem, etc. But now it started losing power, sometimes in critical situations (like up hill on the freeway!) And always when I would slow down at a stop sign or first try to start it up. So I had it towed and was told by my mechanic that it's got 2 bad coils and it needs a new capacitor. I think I'm going to ask that he put in used parts, although they only come with a month's warranty. What do you think??Is this car worth keeping or should I sell it? I don't have any more money really than I could get from selling the car. Should I ask for new parts, not used ones? Please let me know your honest opinion. Thanks! -Gaia