I dont know this car well but window winders are normally held on by one of the following methods
Push back the trim pad and look behind the handle there may be a U shaped clip holding the handle to the splined drive. With care not to damage trim, push off clip with a flat screwdriver.
Alternative
If there is a plastic insert in the winder handle remove it and see if there is a screw holding the handle in place.
Maurice
June 2010