MacBook (13-inch, Aluminum, Late 2008), Unibody Replacement

I recently dented the top exterior shell or Unibody of my MacBook (13" Aluminum - Late 2008). The screen is intact and functioning properly. However, I would like to replace the dented portion. I have briefly scanned the discussion topics but have had little to no success locating an alternative to the obvious; Take it to an Apple Store for repairs. Can anyone offer assistance as to how I may accomplish this at a reasonable cost.