If you are working in a Japanese company or with Japanese clients, then you might need to learn some business Japanese. Of course in business situations too, we use same Japanese. And it's true that there are some expressions that are common in business situation.

If you would like to learn those expressions in a short time, then Business Nihongo Drills is ideal. You can finish this book in one month if you spend just one hour a few days each week to read it.

You can use this book after you've passed JLPT N2.

http://www.unicom-lra.co.jp/jkw/bjd.html