How do i get the full path of the current extension?

General Questions
2

You can use the paths API for that: call overwolf.io.paths.localAppData and concatenate your extension id and your app version to it:

Overwolf.io.paths.localAppData + "/overwolf/extensions/[your extension id]/[version]"

Where version can be retrieved from the manifest.

Another trick is to use the simpleio plugin to get the paths.