Whew! Sure is darned lucky you had that protekshun filter on it! 
Of course a lens cap might have worked even better.
Or - who knows - a high impact plastic bayonet lens hood instead (if only one were available to fit the lens) might have absorbed enough of the blow to prevent jarring the elements inside out of whack.
Now seriously, I feel your pain... I had a similar experience when a camear with a nearly-new 135/2 mounted fell out of my car seat onto the pavement, nose down, then tumbled onceor twice. Probably a 3 or 4 ft drop. Nearly gave me a heart attack...actually broke the lens cap.... and put one or two little scrapes on the lens hood (reversed at the time) and the camera's battery grip. Fortunately, only the $10 cap and very minor cosmetic damage... Both lens and camera still work just fine. No filter on the lens at the time, I don't use protection filters as a rule because with my luck, if there had been it would have shattered and driven sharp shards of glass into the front lens element.
Hmmmmm... Wonder if we could get Mythbusters to buy a few hundred lenses and cameras to scientifically test the "protection filter vs. proper-hood-and/or-cap-instead-of-filter" theories?
You'll need to send the lens to Canon to get a repair quote. It's really impossible to say what's needed, without taking the lens apart. The costs might be covered by homeowner's insurance, depending upon your coverage.