2003 Toyota Corolla Vibrations at highway speeds

My carolla drives very loud and vibrates at highway speeds. The noise and the vibrations seem to be toward the back around the rear axle. About a year ago I had the wheel bearing on the passenger side replaced and seem to cut the noise and vibration down only for a couple of days. Since then I just passed the noise and vibration off as having old tires and needing to replace them. However, a friend said that it probably won't help and that a CV joint might be busted? I thought CV joints were in on the front axle? My question is what might be causing the noise and vibrations and how can I fix it?