P0420 Code 07 Prius 238k miles Bad Catalytic Converter?

I own an 07 Prius with 238k miles. Recently had the check engine light coming on and off for the past few months. We got a lot of rain and 2 weeks ago my master warning light came on along with CEL as I was slowly backing up in a parking lot. I ended up taking it to have codes tested...12v battery needed replacing and P0420 code thrown. I replaced the 12v battery and kept driving. Got the red triangle of death again and check engine light as I was backing out of the driveway the following day. I took it to the dealership...paid $125 for them to tell me it is indeed p0420 and that I needed to replace my catalytic converter. They quoted me about $2300 to replace, which sounds outrageous to me. I change my own oil and know my car burns more oil now than when I bought it at 165k, but I couldnt say exactly how much it is burning. I read on here that if your Prius is burning oil, then replacing the cat wont necessarily fix the problem. That it might be the engine.

Question is-- what should I do? I have a local garage that could put a generic cat on for about $200 plus cost of the part, but is it worth it? Any reliable after market cats out there? Brands or links you could post?

I would replace it myself but understand there is welding involved (beyond my realm of expertise). I see some labeled as direct fit and one was labeled no welding required, but there were no reviews. Anyone able to point me in the direction of what I should do first? Is it okay to keep driving short trips? I was planning on keeping this car for at least another 2 years. Thanks in Advance!