Good question. Temperament, generally speaking, is what you were born with in terms of disposition or general "style." For instance, some people are extroverted or introverted in style. Some are more pessimistic and others are more optimistic. Some are pensive by nature and others are more joyful. All of these can be seen as temperament. Perhaps, the best way to view temperament is to speak of inherited inclinations.
Personality differs in important ways. The most fundamental difference is this: personality is what a person builds on top of their temperament. There is, of course, a inherit component as well, but most of it is due to other factors, such as where you were born, what opportunities you were given, your educational background, and most importantly your social circle.
If you look at it this way, two people with the same temperament could look very different, because of their experiences. Their personality will be different.