You did not tell what brand popup you have ,,, but you can check these ones out :
http://clamoutdoors.com/customer-service/http://clamoutdoors.com/store/index.php/parts.htmlI also read somewhere that other guys did buy a product called Bish's Tear Mender from out door store and cut the patch bigger than hole and applied it. It wa said: For either adhesive cut the patch to overlap by at least 1/2 inch all the way around. Place the patch dry and mark the boundaries. Coat both the area surrounding the tear and the patch with the adhesive and let it dry to the touch. Apply a fresh coat on one of the sides (tear side or the patch), apply the patch. smooth and put some weight on it. Quick, easy and effective.
Hope it helps.