is it possible to run a wireless part without

Greetings,
I have a wired router going to three machines with the a cable internet connection, i would like to make wireless part of the VPN (?) home network, so laptop & PDA can access at times when needed.
Question is: do i have to redo the entire system, (the router & Cable modem are on the first floor, and there is a desktop on floors 1, 2, & 3), the lap top would be only on floor 1 or 2.

 

Wireless and wired can run alongside one another. Adding a wireless segment to a network should not upset a wired network. The thing to make sure is that IP addresses given out on the wireless network do not conflict with those on the wired. If both the router and your wireless access point (AP) use DHCP (assuming you are using seperate hardware. If the wirelss point is build into the router, you shouldn't get a problem), you need to set the IP address assigned by the AP to be different to those given out by the router. For example, set the router DHCP to give out 192.168.0.10 to 192.168.0.50 and the AP to give out 192.168.0.100 to 192.168.0.150.

If you are using static IPs, make sure any IP set on a wireless device is different to that on the wired network (though in the same subnet).