Improving Ride Quality

I am the (un)happy owner of a SR5 2009 sequoia
the ride is just horrible, I feel the slightest road bump in my spine
what can I do to improve ride quality
get softer springs
get softer shocks
get softer springs and shocks
get front and rear air springs (if at all available
none of the above, get rid of the beast and get a lincoln town car