the amount of fabric is dependant upon the size of quilt you wish to make- and the size of the repeats in the fabric- you need at least 6 repeats- so if your repeat is every 12" you need alot less than if the repeat is every 28"...
you could try finding the book at the library- or go to a shop that has it and look through it.
fabric selection is everything to make OBW's work