Where to get a late 2009 battery
I've tried looking for one, and can only find how to replace it.
I need to buy one. Any links would be greatly appreciated. Mine says service battery.
The battery in that model MacBook needs to be replaced by Apple or an Apple authorized service provider.
Contact Apple using www.apple.com/support/contact if you are in a country that supports it or call the appropriate phone number on this page. Alternatively carry the MacBook in to an Apple retail store or service provider to ask for an estimate.
Best of luck.