(Undated) — The national average for a gallon of regular unleaded is up a penny from a week ago. According to this morning’s numbers from GasBuddy.com, the national average is $3.16 a gallon. Here in Illinois, drivers are paying an average of $3.33 a gallon, eight cents lower than a week ago. Across the river in Indiana, the statewide average is $3.05 per gallon, a thirteen-cent decline from a week ago. Oklahoma drivers are paying the lowest statewide average $2.58 a gallon. Drivers in California are paying the highest at $4.64 a gallon…