Hi Tantaurus and welcome.
Hopefully, someone else will have an answer, but, I think I would just double the crust recipe...that way surely there would be enough, and maybe a bit left over...or maybe just get one of those packs of frozen pie crusts where there are 2 in the pack....hope that helps.....
So, what is it that you are making in that 9X13 pan?
2 cups flour1/2 cup ice water ( Must be ice cold)1 tsp salt2/3 - 3/4 crisco shortening or butter flavor shortening.
Mix flour, salt and shortening tog, add water mix till incorporated ( the less mixing the more tender the crust). Roll to desired size.
Left overs roll out, spread with butter, sprinkle with sugar, cinnamon, nutmeg roll up slice, and place on a greased sheet and bake. These are yummy!