Regarding books, generally students only need two books:

1. A prep guide from one of the reputable test prep companies - the book you have from Kaplan should be fine. This book will give you the foundational info and strategies you need to attack GMAT questions appropriately.

2. The big orange GMAT Official Guide. This book is awful for explanations and strategies, but excellent in that it provides you nearly 1,000 actual old GMAT questions to practice.

My approach to studying is to learn the strategies from a test prep guide, then practice applying those strategies to the problems in the Official Guide. You will get nothing out of studying if you simply try to fly through the problems as fast as you can. Analyze every right and wrong answer and study them in relation to the strategies and concepts you learned from your prep guide.

If you need more, first, ask yourself if you truly analyzed each and every answer choice to each and every problem in the orange book. If so, then go ahead and get the other two Official Guides - one is verbal specific and one is quant specific. They will give you another 800 questions. If you're particularly low scoring in verbal, you might want to buy a basic math workbook (non-GMAT related) too.

Too often, students go nuts and go out and buy a dozen prep guides, sacrificing quality for quantity.

As for business schools, there's lots of great schools around the country - average scores at the top schools average a bit above 700. Santa Clara is generally regarded as the next best program in the Bay Area, after Berkeley and Stanford. We at Veritas have a fun little online tool you can use to get a list of business schools at which you might be a good fit, admissions-wise at least:

https://www.veritasprep.com/selector

Good luck and happy studying!