MWAHAHAHA!!

I have sorted it out. I had tried to use the wrong tool to set up the workgroup for the computer, and so stuffed the wireless network settings. All is well again (as I suspected it would be), and the workgroup is set up. Now we should be able to share the printer. I just need to find out if the network signal stretches to the other end of the house ...

I am so pleased. I have proven myself my father's daughter, even if it took me a few days (only about three or four hours, though).