Macbook Cannot Sustain Charge; Crashes at 84%

[diametric]

For a few weeks/maybe a month or two, my Macbook cannot hold a charge.
iStat Pro says the battery health is 74%, Ive had it for a bit over a year.
And, earlier today, my Macbook crashed half an hour into watching a video whilst being powered by the battery which was at 84%.
So.
Im thinking, it MUST be something else.
Power up, less than a minute in, it crashes again, and again.

Do I call Apple?
Do I buy a new battery? And I should not have to do that.
There's obviously something wrong.

If someone could give me some advice, especially if theyve been involved in a similar situation, it would be greatly appreciated.

Thanks.

 

[iBookG4user]

I'd call Apple, there is definitely something wrong with your battery.

 

[kolax]

How often did you calibrate your battery? (i.e. leaving it switched on while running off the battery until the battery completely runs out)

 

[Osarkon]

Crashes in what regard? Kernel panic, or just shuts itself down? Or freezes?

 

[EricNau]

You may want to read this:

http://www.apple.com/support/macbook_macbookpro/batteryupdate/