While shocks will clearly help with porpoising and ride quality, they are NOT the first thing that comes to mind for controlling sway. Were shocks valved stiff enough to control side to side motion, they would beat you to death over regular bumps.
First thing to check is the sway bar bushings. If any play/you can see air around any bushing, replace with polyurethane bushings.
You don't mention what chassis you have, but with front leaf springs, I assume it is Ford. Get the ride height specs for your chassis and make sure the springs/(supplemental air bags if installed) are OK. This also means making sure that the tag axle is properly adjusted-- if it is not carrying enough weight, the rear axle will be overloaded and front axle underloaded. If too much weight on the tag, it can overload the front axle. Too little weight on the front axle WILL make it tough to handle.