You're on the right track, but still too high.
Crude oil is not crude oil. It comes in countless grades and qualities which determine how much gasoline can be refined from each barrel. Some are much better than others.
A good average would be about 19 gallons out of a 42 gallon barrel.
This was an amazingly accurate article issued by the AP, though. I never would have believed it.
It even accurately stated that many refineries are losing money right now, something which the majority of Americans would automatically dispute.
It's worth remembering that AP is a news service and not a news outlet. The subscribing news outlets (more like partners, I think) choose which of the many news reports to print.