You should get Gipps Understandable History of the Bible. It really lives up to it's name, is a very easy read, and is comprehensive enough to give you the information to rebuke the scoffers.
God bless
Luke
Online -
http://www.samgipp.com/historybook/ - this is the older edition
Buy -
http://daystarpublishing.org/shop/in...p?productID=97 0 newer bigger better edition.