the radio button is just called a "control knob" RealOEM.com BMW E60 525i Controller up to 09/2008
they're pretty pricy you're probably better off buying one from the dealer...although theres this website never tried them though... http://www.ddmtuning.com/
the cotrol knob comes up if you search it with the part number.
and RealOEM.com BMW E60 525i Window lifter switch, driver's side
As for the plastic cover for the window switch i highly doubt anyone sells it by itself, you'll probably have to buy the whole assembly. Theyre about $70 on ebay, if you search for "e60 window switch" youll find it You can always search around for a decent one at a salvage yard if you really dont want to do that.
Good luck on your search