Download and install Ubuntu 12.04 or 13.04 which are the supported versions at the moment, and perhaps already include the driver for your wireless card.
8.04 has been unsuported since long ago download the 32bit perhaps if your computer doesnt support the 64bit flavor.
this is the link www.ubuntu.com
If your video chip is limited perhaps you can download and install a light weight graphical interface version such as Xubuntu or Lubuntu
Good luck to you