macbook pro battery running low

[narvin1]

my MacBook pro was purchased in 2009 recently it indicated a battery low problem ,it works well with the powersupply adapter , i usually update my mac presently it has the , ios5.? update , what should i do to fix this problem also the battery counter has a malfunction it would indicate 80% then down to 32% within 5mins the actual condition of the mac is excellent need some help urgently.

 

[kch50428]

Batteries do wear out... replace it.

 

[rjkgr]

you can replace or by a external battery like i did!