Hi Button,
Welcome to the Mattress Forum! 
Adding a topper certainly could assist with surface comfort modifications (adding plushness), but I’m not sure how much of a difference it will make with the “bouncy” nature of the mattress. Obviously putting more distance between yourself and the innersprings of the mattress (and perhaps coils of the box spring, if the mattress set uses an actual coil box spring unit, or even a torsion modular unit) can help dampen some of the motion waves (mostly the smaller surface waves), but I don’t know how effective it would be for the motion transfer. If you did add a topper in this particular situation, I would do so with the expectation that you’ll make the mattress more comfortable, but it will more than likely retain much of the motion “bouncy” characteristics. That’s the best advice I can offer without being in front of the actual mattress and knowing the complete construction and integrity of the construction.
You can check with some of the businesses in the Stuart / West Palm Beach area listed in post #2 here and see if any of them offer the type of topper you desire.
I hope that helps.
Phoenix