Start with the 70-432 book, it's less advanced than 70-450. However, those books primarily focus on administration, and not on developing (TSQL et cetera).

You could also start with this book:

Microsoft® SQL Server® 2008 Step by Step

You can also start with SQL Server 2012 and get up to date with all the latest features.

Try to get your hands on a developer edition and try things out yourself.