As promised, here is the book list for Business Planning (with a little help from Amazon, of course):
Casebook: Drake, Business Planning: Closely Held Enterprises, 3d (American Casebook), (3rd 2011) (this is an excellent book that I expect you will want to keep)
Statutory Supplement: Lathrope, Selected Federal Taxation Statutes & Regulations, with Motro Tax Map, 2012, (2011) (I will be using this new version, but the one you used for Business Tax should be fine)
Also, remember that students can sign up for free two-day shipping for six months with Amazon Student.