headlight headlamp parts

:( Somewhere, somehow, whatever ... the rubber cup that attaches to the back of the housing for the low beam light has fallen off. I am not sure if it fell through or is somewhere in the bowels of the front of the smartie. Does anyone have one for sale. I have to have it as moisture is seeping...

I was wondering if anybody has had to replace a headlight yet and what it cost. I have a cracked passenger side headlight :(