What color was the car that you bought?

The only good color for an Renault 12 Gordini (or a Renaud 8 Gordini) was blue with the two white stripes, as on the picture.
You could also buy it in yellow, but 90% of the R12 Gordini were blue.

In those days owning car must be a great achievement or maybe only rich people can afford it?

No, in 1972 you did not need to be rich to buy a car. The R12 Gordini was then an expensive car (20,000 francs, ~ US$4,000) but you could buy much cheaper cars, such as the Citroën 2CV for less the US$1,000.