I bought the power window switch on ebay for the driver side. Been working for 3 years, seems they just break when you stress them to much.

 

I really doubt you will find just the cover anywhere. You should be able to get the whole switch assembly at a salvage yard for about $25. If you can get the cover off of the switch without breaking it you might be able to avoid taking the door panel off to replace the whole assembly.

 

You don't need to remove the door panel to replace the whole switch assembly. The Cover (the part that surrounds the switches) will pop right off the door. You need to gently pry it up with something that won't damage or break it, but it's not difficult to get them off. You can then remove the switch assembly by removing a couple screws. You can then disconnect the wiring to the switch. It's kinda easy and you should be able to find a switch assembly on ebay. Don't think you'll be able to just find the lever part of the switch that broke off.