So the PC is standalone, with no network connection?
Any particular reason why you want a wireless printer then?
Basically the simplest thing to do is get a wireless dongle for the PC. The range on these is quite short, so if you're chosen dongle doesn't come with a desk stand get yourself a decent USB extension lead so you can put the dongle up high on a shelf.
Set up a Ad Hoc network with the dongle, instructions should be supplied. Attach the printer to the PC using USB so you can access the settings and set up the driver, then set the printer to recognise the Ad Hoc network.
Bod should then be your mother's brother.
Some printers are easier to set up than others. My HP was a doddle, but a friend's Lexmark was a nightmare...