I was also a sociology major in undergrad. I wouldn't worry too much about theoretical orientation. The most important factors in working with clients involve the relationship: how well you listen to their concerns, how well you communicate to them, trust, your ability to adapt to change. Always listen to your clients and treat them like people. There is nothing that your clients have experienced that you can't relate to on some level.
You will get plenty of info about various theories (you'll likely take a survey course of all the major schools of thought).
I would try *Duncan/Miller's: The Heart and Soul of Change http://www.amazon.com/Heart-Soul-Change-Delivering-Therapy/dp/1433807092/ref=la_B001IO8CRA_1_1?s=books&ie=UTF8&qid=1388808048&sr=1-1 Wampold's: The Great Psychotherapy Debate http://www.amazon.com/The-Great-Psychotherapy-Debate-Investigating/dp/0805857087 Dawes': House of Cards http://www.amazon.com/House-Cards-Robyn-Dawes/dp/0684830914 Szasz's: The Myth of Psychotherapy http://www.amazon.com/The-Myth-Psychotherapy-Religion-Repression/dp/0815602235 *Szasz's: The Ethics of Psychoanalysis http://www.amazon.com/The-Ethics-Psychoanalysis-Autonomous-Psychotherapy/dp/0815602294 *Frank's Persuasion and Healing http://www.amazon.com/Persuasion-Healing-Comparative-Study-Psychotherapy/dp/0801846366/ref=pd_sim_14_1?ie=UTF8&refRID=13GG5CD76HZEG25XKBM9
Good luck!