Thanks Abliblablobla,
Unfortunately I cannot wait till Summer, as I am trying to finalise a few things before I submit my game to the AppStore and Google Play in a few days.
I have found a temporary workaround and I thought I would share it here, until the proper events are implemented.
I simply used "when the game loses focus" event. So as soon as the player clicks on the Admob Ad, it pauses the game by displaying a big pause button in the Scene. When the player returns to the game, they simply click on this button and the game resumes.
I have tested this on an iphone5, ipad3 and sansung galaxy s3 and works like a charm.