early death of battery

Welcome to the Apple Support Communities

See > http://www.apple.com/batteries/notebooks.html Unibody MacBook batteries are designed to have 80% of their capacity after 1000 charges, so this battery looks like it's defective.

You should take the computer to an Apple Store. If your computer is under warranty or you purchased AppleCare, it will be replaced for free, but if it's not under warranty, you will have to pay to get your battery replaced

You can contact with Apple > http://support.apple.com/kb/HE57