Well, speaking about the lawyers fees, the sky is the limit. ;) I know typically a good and expensive lawyer firm can charge around $15K for the family of three (well, this includes the official payments for the process, but doesn't include the medical exam and a few more minor fees). You can always negotiate though.

I've been working with David Fullmer from Ivener & Fullmer, LLP. The web site is http://usworkvisa.com/. You can contact me personally and I can provide a reference. They are based in Los Angeles.