It bolts up from the bottom, but replacement is a breeze. Did the shock shaft go through the mount? Seems to be a relatively common occurrence. Sometimes, when it does it, it sorta presses itself into the mount, and you have to get a new shock also.
Just pop the cover off from inside the trunk, remove the two nuts, take two bolts off the bottom of the shock, and you have it out. Before you remove it, you may want to take the large nut off the top of the shock while it'* still in the car.