On your wife's computer, turn the settings on to share the printer.
On your computer, go to Start > Settings > Control Panel > Printers and Faxes
Then add a new printer. Add a networked printer. You may be able to browse and Windows might be able to automatically find it. Or you can copy your wife's local IP address (of the computer), and it will find it from there.
Only thing is that your wife's computer has to be always on if you want to print documents wirelessly from your computer.