Problem with emission/smog

There are some problems with my car, and I need your help to diagnose. Thank you very much in advance.

The following is the smog check result:
Test-------RPM----CO2(%)---O2(%)---HC(PPM)---CO(%)
idle--------675-----13.7-------0.00-----207---------0.6
2500RPM--2706---14.3-------0.00-----124---------0.81

Problem: HC level is too high for the idle mode and both HC and CO levels increased a lot since the last smog check 3 months ago (see below please), while O2 level is lower.

Car condition in the previous smog check (3 months ago)
Test--------RPM-----CO2(%)--O2(%)---HC(PPM)---CO(%)
idle---------644------13.2------3.1-------76----------0.09
2500RPM---2532----13.4------2.4-------37----------0.50

Recent activities:
I changed the radiator, which leaked but the engine was not overheated.
Did a tune-up and changed the plugs and wires, which didn't help.
The car has been running great, and mostly on freeways.

PS:The car is Oldsmobile Cutlass Ciera S 4D, almost 200000 miles.

I feel like an idiot saying this but I think your should check your exhaust system. LOL...wow, I don't know shit about cars. ALSO, check your catalytic converter, kuz I know that I have to change mine soon in order to pass emissions test. It's like $200 or so!