87 300e euro failed emissions/ smog test. What to do?

[lorainfurniture]

I went to the local e-check today, and was really disappointed...

HC: @2500rpm limit: 220 Reading: 286.4 fail
CO: @2500rpm limit: 1.20 Reading: 7.88 fail
CO2: @2500rpm 6.38. (no limit)

HC: @idle limit: 220 Reading: 449.0 fail
CO: @idle limit: 1.20 Reading: 5.10 fail
CO2: @idle 4.07

Gas cap: PASS!!!

The car was at operating temp, I just filled up with 92, plus a bottle of octane booster.

Im burning through gas like I got a hole in my tank.. Im guessing about 200 miles to 16 gallons (12-13mpg)

The O2 sensor was put on after the fact. Part of the fed process I guess.
The car is originally from Belgium..

Where do I start?