So I ordered a reinforcement kit from a guy over at the Impala SS forum. That will help stregthen the arm rests and hopefully prevent future breaks.
I am thinking of either using fibergalss to patch the hole and then use JB Weld or getting some spare plastic and a soldering iron and plastic welding the cracks. The passenger side is a thin hair line crack, so JB Weld and some SEM should do. The drivers side has a large hole though, big enough for a nickel. That will require some plastic welding. I will post pics of my progress. Stay tuned.