If she already has M$ Office she can load it onto her new PC: I could be shot down in flames on that statement as I am not sure which older versions are compatible with Vista.
Technically you are allowed to load Office onto your PC and your Laptop, the accent being on "Your" as there is only one user. She should be able to run it on 2 PCs, in the same house, I don't reckon that there would be any serious complaint.
To save a l;ot of money she can use Open Office which is very similar to Office and is compatible...it costs nothing and is excellent...click here
I would get her to have a look at Dell, their prices and delivery are excellent. You can buy a wireless dongle for around £12 click here for £369 is a cracker and comes with a 19"TFT monitor and Vista.