How to quickly add 2 seconds to animation in the middle of the composition?

Hi!

I have a finite composition. The composition comprises a plurality of layers, a plurality of layers correlated audio, there are also compositions nested.

Sorry. One of the animation (the scene) must extend about 2 seconds

How to do it quickly and without loss of stacked layers and correlated composition?

I want to do something like this.

http://cl.ly/1m341Q3M0V1E

Best regards!