I found this # on line.
(800) 328-6596 for Cole sewell
If that does not work I found this on line:
http://www.bizjournals.com/twincities/stories/1997/11/24/story8.html
Basically states Pella Bought Cole Sewell. So you may have some luck contacting Pella.
Their service request form can be found here:
http://www.pella.com/support-center/request-service-and-parts/default.aspx
If you call be prepared by having your model number ready. It may be printed on the frame or along an edge.
Greg
Webmaster
Winter Park Real Estate