Does the battery actually need replacing in your opinion? You could also check the status in more detail with coconutBattery.
I believe that just means you hit the charge cycle count. It isn't actually based on the performance of the battery....
Apple will do it for you for a fee. Be careful about installing a third-party battery, as it could cause damage. Maybe if you find an OEM Apple battery, it would work ok, but apple doesn't sell them directly.
I had to replace a battery in a 2010 15-inch at the Apple store, and I think it was $129 installed.
I believe that just means you hit the charge cycle count. It isn't actually based on the performance of the battery....