Try Hearland and also Vaghan Mills Centre http://www.vaughanmills.com/Planning-Your-Visit/Getting-Here.aspx
These will be 2 concentrated locations with many stores under one roof.
You could try Bruno Magli
If you want to try downtown, you could try David's Shoes at Bay & Bloor
http://www.davidsfootwear.com/ scrol to the bottom of their page and click CONTACT for their phone number.
Inquire by phone if they even carry your size. David's is having a mass clearout sale...