try this site for resizing.
http://www.sensibility.com/pattern/resizepattern.htm
and read
http://www.fashion-incubator.com/archive/drafting-to-measure-pattern-book-recommendations/
"Learning to grade is easier than learning to make patterns. The more important point is that it is less work to grade a pattern than it is to create an entirely new draft for another size. They’re looking for a book to draft in all the various sizes when their time is better spent in learning how to grade. Put more to the point, drafting takes much longer, grading is 1/10th the time (estimated)."