Integration applied to Physics problem

Ok, here's the problem: "A gas station stores its gasoline in a tank under the ground. The tank is a cylinder lying horizontally on its side. (iIn other words, the tank is not standing vertically on one of its flat ends.) If the radius of the cylinder is 1 meter, its length is 5 meters, and it stop is 4 meters under the ground, find the total amount of work needed to pump the gasoline out of the tank. (The density of gasoline is 673kg per cubic meter; use g=9.8m/s^2"

I've got an equation for total work that says that Total Work is equal to 32977* the integral (from 0 to 2) of w(6-h)dh with "w" being the width of the cylinder and "h" being the height.

My issue is that I can't figure out a formula by which to convert w to h; only by doing that can I solve the problem. So does anyone have any suggestions? Any help is appreciated.