http://www.worlduph.com/e-mail.html
Rick -- World Upholstery (link above) offers to send a free sample -- it might be enough and if not you might ask them to sell you a piece of material of sufficient size.
I recall reading a post or web site where someone suggested taking a piece of matching colored material, and good upholstery (or otherwise waterproof) glue, sliding the patch piece under the tear and gluing the the original torn flaps down onto the patch -- you would get the most unnoticeable repair that way, I think.
Regards,