Needinups

Hey what's up everyone!
First of all I admittedly am a car noob. Lol...
Anyways I bought a 1995 civic si 2 dr coup 1.6L
The car drives relatively ok if you don't run it past 2k/rpm. The engine light is on. The Srs airbag red light is on. There's a hole in the exhaust. I believe everything is stock? It has decent looking tires and rims. Has a bad custom paint job. Has about 289,000k on the odo. The hood has hail damage. Roof is fine. May have been in am accident at some point just because the paint job providers sticker is still in the car.
I paid $2k it's safetied. I've been driving it. The tires and rims are actually worth about 1k. I'll post pictures soon.
When I attempt to accelerate quickly. 3k/rpm or higher. Sometimes the tranny seems to slip. I was told by a buddy that this may be caused by the catalytic converter which is not allowing my exhaust to leave the engine quick enough because the cat converter is clogged/plugged etc. I do see exhaust leaving the tail pipe but was told that may not matter. It still could be plugged.
What can I do with this car? I've been looking for complete exhaust system after aftermarket upgrades. Should I waste my time? The engine has a lot of k's but I'm willing to put a little money into this cheap car if I can make it last me a couple years. Perhaps more.

Needinups

So should I spend some money on this old engine? Anyone have any recommendations on upgrades? Websites? Forums. Etc. any input is greatly appreciated.