Help! What hardware to buy Networking

Help! I have just purchased a new MacBook Pro and need some advice around Networking.
I will be using my new MacBook and my wife her own Windows Laptop both wireless. I would like to set up a new wireless network to be used by both with a n external HDD which we can both access wirelessly to back up files, and access tunes and photos. But and it is a big but i have no idea what i need to buy to do this???

anyone got any ideas on what i should be looking at buying with a reasonably tight budget?

Thanks

Eypdas

The airport extreme will work well - but it isn't cheap. If you plan to use a USB printer as well as the external HD at the same time, you can use a firewire cable for your HD and a usb for your printer. The extreme has one USB port.

Thank you, i had looked at the Airport Extreme but as you stated it is expensive.
will probably end up with it though