Hi Me 
This doesn't answer my question, but at least I can do some "gleaning" and make approximate statements. I just noticed this :
Article: ecomodding a vanilla Renault production sedan... efficiency up 19%
http://ecomodder.com/forum/showthread.php?t=179
Quote:
The sum of all the work that went into Logan Renault eco2 Concept achieved record low CO2 emissions of just 97g/km (NEDC combined cycle) equivalent to fuel consumption of 3.8 liters/100km (62 mpg US).
Furthermore, the extraurban phase of the NEDC driving cycle returned UTAC homologated fuel consumption of just 3.4 liters/100km (69 mpg US), equivalent to CO2 emissions of 88g/km.

This implies the following ratios :
97/3.8 = 25.52
88/3.4 = 25.88
Pretty close! We'll take the average for a constant of 25.7.
Now, I know that my car is currently getting 41.35 MPG, or around 5.66 liters/100km. Plugging that in we get the following :
X(g/km) / 5.66 = 25.7 => X = 25.7*5.66 = 145.46 =>
CO2 emissions of 145 g/km
EDIT : This is not right. I am comparing the performance of a diesel to my gasoline engine. Gotta go do some more homework.
CarloSW2