try B&Q

I don't know if this will help you. You can try to locate an appropriate business in your area by searching in www.googleearth.com
In the Google search window on top of your screen, write for example, furniture,hull,quebec then click on the blue and white ball beside the search window. Let me know if you need more instructions. charles_madaire@hotmail.com

My guess is that this is not the type of item you will be able to buy "off the shelf". I would remove the old covers from the chairs and I would start my search by visiting area fabric shops. In addition to providing you the right fabric in the color of your choice, they should be able to recommend a seamstress or home hobbiest to make them for you. I'll bet someone in your area would like to earn a little extra money by sewing your new covers based on the size of the old ones you removed.

Good luck with your project.