If you have a neighborhood hardware store nearby, they might have something that would work. My local hardware has all sorts of specialty fittings like that. The color and style may not be a perfect match, but I think the threads are fairly standardized.

That appears to be an alabaster up light. I don't know where you can find a replacement canopy. Can't imagine how the canopy could be damaged unless the fixture was simply pulled off the ceiling. Do not use high wattage bulb in this fixture as the stone can discolor from heat.

Check EF Chapman Lighting

Oh, I cut and pasted the chandelier you posted and put it on my desk top. Then I used images.google.com and added the image. The chandy came up right away. Images doesn’t work all the time, but if you are lucky and it works, you have your answer in seconds. I wasn’t going to tell you ‘cause I wanted you to think I am a design magician. )