Yajhershey

Hello, I own a 2000 civic hb with b18c1 bar, it came with dc headers when I bought it, I have owned it for 18 months and only put about 3500 miles on it. ATM i have a cel for p0133, it's driving me nuts, it only has one o2 sensor by the cat, so far I checked for exhaust leak at the shop and changed o2 sensor, they told me its my o2 sensor, I said that I changed it already and it's not even that old, I asked my friend who's knows about honda stuff, he said my dc header is ob1, since my car is wired up for ob2, how do I get rid of the problem and just make my car run right? I looked under my car and it looks like wires were cut by my headers, so there is only one 02 sensor slot, the shop said I might have to relocate my o2 sensor but I don't know if It will solve my problem, or my friend has a stock oem header I can have for free but do I need o2 sensor for that, help me please, I'm about to punch this car so hard lol