Upgrading from Pg 9.1 to 9.2

Howdy,

I want to upgrade my Postgresql server from 9.1 to 9.2 on ubuntu 12.04
but when I did the following ubuntu created a new server (on new port)
 instead of upgrading Postgresql  & migrating the old data!

sudo add-apt-repository ppa:pitti/postgresql
sudo apt-get update
sudo apt-get install postgresql-9.2
sudo apt-get upgrade

Is there any specified steps I've to do?

--
Best Regards
Muhammad Bashir Al-Noimi