I used the seventh edition which isn't supposed to be much different from the sixth, just with a new section in each chapter with graffiti from Pompeii. I found it interesting, at least, but it's not essential. If it saves money to go with the sixth edition you're probably not missing much but the book is so cheap that it really doesn't matter.
There are CDs of the vocabulary lists and exercises but I never got them. There's also a workbook, but there are so many exercises -- a good many in the chapters themselves, plus very generous supplemental exercises in the back of the book along with the answers -- that I'm not sure the utility of it. There's also Thirty-Eight Latin Stories Designed To Accompany Wheelock's Latin
which I never bought (though the more you read the better) and Scribblers, Scultprs & Scribes
about which I know nothing other than that it gets lousy reviews. Wheelock's Latin Reader
is meant to be read after the introductory textbook (which itself includes a number of adapted and unadapted readings in the back).
Note that the book doesn't come with an answer key. There's one posted online from an East Asian student (who consistently renders the word "patria" as "the patriot") that has a few mistakes and at times betrays a lack of reading comprehension on the part of the student that nonetheless is serviceable enough. I've heard that the publisher's answer key is hard to come by. I'm willing to help some, as would undoubtedly others here. I'm not an expert but helping with the exercises in Wheelock's shouldn't be a problem.
About an Attic Greek textbook: I used Mastronarde to learn the basics but it's hard to recommend to an absolute beginner because of the merciless pacing, dearth of exercises, overreliance on English-to-Greek translations, and lack of examples. On the other hand it's very thorough and clear, though if I didn't have any Latin experience I'd have been sunk. All in all it's a decent book but it reinforces the material so poorly (often only one or two of the exercises use the grammar covered in the chapter) that I've found myself having to go back over the Mastronarde chapters while reading the Anabasis, and a good many vocabulary words -- including important adverbs that are hard to learn without seeing them in use -- aren't used in the book at all. I've heard good things about Athenaze but the materials cost a small fortune. Aside from that I know nothing about the texts. You'll probably get good recommendations on the Greek forum.
Edit: Here is that online answer key. It's based on the sixth edition but there's not much different from the 7th (and, again, it's not very graceful):
http://www.shochian.com/wheelock_Latin_ ... rs1-20.htm
http://www.shochian.com/wheelock_Latin_ ... s21-40.htm