As of today, 2008 March 02, your average opponent rating is 1352. Your rating, not score, depends on the ratings of your opponents. Your rating will increase slowly if you continue playing lower rated opponents.

You can change your online chess settings so only players rated higher than you may challenge. http://www.chess.com/home/echess_settings.html

Maybe some of the games was unrated games. When you play unrated games your rating will still the same no matter you lose or win