I think most any even halfway decent shocks would be a significant improvement over what you're dealing with at present.
I have Koni FSDs on my motorhome and I've been quite pleased with how well they work. They are not particularly inexpensive, and I can't say from personal experience if the added cost over other shocks is completely justified. (They have a special valving system that lets them act as a relatively soft shock for minor disturbances but a heavier one for major bumps, so as to give a smoother ride while still providing proper control.)