Question

What is the difference between extend and upgrade warranty?

Answer 1

Upgrading warranty means you already have basic cover for the laptop and you want to get higher cover eg, if you have basic break down cover, you can upgrade it to have accidental damage 

Extending warranty means that your current warranty is expiring and you need to get the same cover for a longer period of time, In your case I think you need to extend the cover

Answer 2

Extend warranty means the current warranty is expiring and you need to get the same cover for a longer period of time.
Upgrade warranty means you already have basic cover but want to get higher.