Equipment Support > Hardware By Brand > Linksys > Best Linksys wireless router suggestions for a big house?

You're going to need more than one access point. My rule of thumb for a residential access point is 40ft. radius.

The 100 ft is probably diameter and that's pushing it. Just remember, as the distance between the PC and the access point increases, speed decreases. You can buy an access point or another router and configure it as an access point. Do you have the ability to run a cable between the existing router and other locations say via the basement?

I was talking about running a cable to another location for a second access point. You can try a wireless bridge but your client probably won't be happy with the performance. There's really only one way to obtain good wifi coverage and unfortunately, that involves running cable.

No attic either?

So run a CAT5 cable from the existing router to a more central location via the attic and connect an access point. Pretty easy solution.

You can use the WRT54GL as either the router or access point. Ideally, you could use a ceiling mount POE access point. The CAT5 cable would carry both the signal and power to the access point and then you could just mount it in the ceiling in a place most central. I really don't recommend putting a unit in the attic. It is a powered device and sometimes the A/C adapter gets hot and you don't want a fire up there. Let me think about a ceiling mount A/P that's easy to configure.

If you're going to try to test it "live" you'll need to go into the setup on the 2nd device and set the IP address to something different than the one by the modem. You also need to set DHCP to DISABLE.

If you have an Android phone, there's a WiFi Analyzer app.