What is the version of the following sentence with correct punctuation?

We had just passed through a small village when we observed coming in the other direction on the right hand side of the road at speed what we though were headlights of a small car possibly the size of a Mini
We had just passed through a small village when we observed coming in the other direction, on the right hand side of the road, at speed, what we though were headlights of a small car possibly the size of a Mini.