You may be able to find a supplier of the same or similar micro switches but it will be a long search and they tend not to last very long - too small to be robust. They may also expect you to buy in bulk.
An alternative may be to fit a bulb holder with a switch like this...
http://product-image.tradeindia.com/00098396/b/Lamp-Holder-Brass-Push-Bar-Big-.jpg
If you can get it to fit. Good Luck...
Peccavi
December 2008