Is it my Alternator or do you have another Idea of what it could be?

I started driving and my secong gear was clunking then I drove about 15 Km and then all my light died, wipers and radio. About 5 minutes later I was loosing power in the gas and then my car died. About 5 minutes later I could start my car and move it just into a parkng sapce. I started my car and took the black wire off my batterie and my engine died. The Alternator belt has good tension I drove it back home with my father recharging my batterie once. I installed a new alternator on October 30, 2011. I might have broken a wing but it worked perfectly fine until yesterday. Today me and my father are going to change the alternator again because I have a lifetime warranty on it. Well let me know if you think its something else. Thank You