Here's how you can upgrade to GNOME 3.8 in Ubuntu 13.04.
1. Open a terminal window.
2. Type in the following commands then hit Enter after each.
sudo add-apt-repository ppa:gnome3-team/gnome3
sudo apt-get update &&
sudo apt-get install gnome-shell ubuntu-gnome-desktop (use this command if you don't have GNOME Shell installed)
sudo apt-get update && sudo apt-get dist-upgrade (use this command if you do have GNOME Shell installed)
3. Reboot your Ubuntu 13.04 system and login.
For more, see the original article at the link below.
How To Upgrade to GNOME 3.8 in Ubuntu 13.04 | OMG Ubuntu!