N5010

Please can you confirm the Make Model and OS, along with any configuration details like touch screen, backlit keyboard, SFF or tower etc etc.

There are many re-sellers to choose from, and geographically diverse.

NB: Dell are not really battery makers, so buying from Dell or a 3rd party can result in the same product.

For a system this old, only third party batteries are available.  Check your local computer store or online for a price.