reinstallation of Ubuntu using twin hard drives

 I am going to install another second hard drive to replace a 160 GB with a 500 GB and I want to save the installation I already have which is a single boot of Ubuntu 9.10 onto the existing 500 hard drive or a 1TB external hard drive I have also installed using a backup program for Ubuntu 9.10 or using the prompt which is a little beyond my skill level at the moment. The 160 GB hard drive is my boot drive, btw. How do I do that?
 If I could at least rebuild Ubuntu with a copy of my personal settings including backgrounds and so forth that would be satisfactory but I would prefer to duplicate the entire 60 GB of files in my current installation.

                                                                                                                          Thanks, Galen