Do you want all 3 PC's to connect by wireless?
In the past I have used a WiFi ADSL Modem Router to connect a Dell desktop via USB cable and several laptops by WiFi. However I now use LAN for the Dell and continue with WiFi for the laptops.
We are BT Broadband users and haven't had any problems with 3rd party equipment.
I'd buy a WiFi ADSL Modem Router and use either inbuilt mini-pci WiFi cards in the laptops or PCMCIA WiFi cards. USB WiFi dongles seem to be more of a problem but