Did you contact the manufacturer?
Ray-Ban Official Site
If all fails, but a cheap pair and transfer both earpieces over, even it it takes a little super glue to hold them on.
Or, see if there's a busted pair on eBay that you can "part out". People sell broken crap on eBay all the time. Or a cheaper pair of Ray Bans that the earpieces may work. Or some $10 knockoffs from a mall kiosk or guy on the corner.