Have you tried this site:
http://www.quiltshops.com/ Since you already know what fabric you want. Just type in the name of the pattern plus the word SALE, and it will give you all the sites that have that fabric on sale at this moment. I never pay full price for my fabric. Granted there are also some sites out there like:
http://www.5bucksayard.com/
http://www.fabric4less.com/
http://www.fabricdepot.com/
http://www.quiltfabriccloseouts.com/
http://www.thousandsofbolts.com/
that are not at QuiltShops that have good prices also. So shop around and get your money's worth.