Peachesbackwards

I bought my first new notebook about a year ago, a Toshiba Tecra A8, and at the time the battery that came with it gave me about 2 1/2 hours of power approximately. I only use the notebook at home and now a year later the battery at full power is only good for about an hour. 1. Is this normal? 2. Am I best off buying a brand new battery instead of a used battery is it holds a 2 1/2 hour charge? 3. Do companies ever come out with longer batteries ( say 6 hours instead of 2 1/2) for the same series or is that it? If they do, how do I find out about it? Thanks for your help.