What is the difference between torque and horsepower in the Audi A2?

I've heard both terms used when talking about car power, but what do they actually mean and which one should I focus on when choosing an Audi A2?

Torque is a measurement of a vehicle's rotational force, while horsepower is a measure of the vehicle's overall power output. In simpler terms, torque is what gets a car moving from a stop and horsepower is what keeps it going at higher speeds.