that really sucks as it was a nice little 
sign.  have they had issues in this area of town? any colleges near by?  those little jerks ruin 
signs for the fun of it around here.  big thing to do is to jump kick the ones all along the road from campus to town.  you may be able to patch with bondo if this was a one off kind of thing.  if it is a bad area for this, an aluminum post and panel 
sign might work better