How install premium version as 'rooted'?

[56Kruiser]

In the past, there was an option in the AVAST software settings to get it rooted. I cannot seem to find that, and hence, cannot set it to turn on GPS.

What do I need to do?

[Lisandro]

When you install AntiTheft you can choose to install it rooted. If you did not do at that time, uninstall AT (through avast! Mobile Security interface > settings > wizard...) and install again.
The avast! Mobile Backup also has an option to go rooted. Once rooted, you cannot return back. You need to uninstall and install again.