The American Psychological Association has a nice document on how to efficiently do literature searches. In addition to the databases outlined in your text that may be available from your university library, the Internet offers a variety of literature search resources.
Many academic libraries allow access to their facilities via the Internet.
Then select the specific library you would like to work with. Follow the instructions on how to gain access to that library's resources. Remember, not all libraries will all you free access. An excellent general library resource is the Vaughan Memorial Library of Acadia University where you will find a wide range of online library resources to help you track down research. Try this one out, it is worth the trip.