This is a great question. The first point that must be made is that there are so many books on this topic that you will not be able to exhaust all of them. So, you will have to be selective. In order to do this, I suggestion a few strategies. First, read a recent book on this topic from a reputable scholar, so that you can use his or her bibliography. In this way, you will be able to know the general scholarship in a responsible and quick way. Second, follow up with a few of the books to gain different perspectives. Third, use an online database and look for articles through keywords. Since you are a graduate student, your school should have access to databases like JSTOR. Now let me recommend a few books.
You might want to start off with: Alasdair Macintyre's The Unconscious: A Conceptual Anaysis. This is not an easy book to read, but he is an amazing scholar and his bibliography will be great. It was also published in 2007. So, it is current. For an easier read, try: Margaret Muckenhoupt's Sigmund Freud: Explorer of the Unconscious.