Here is a low cost option to reliably increase the range of your wifi. My linksys wrt54g2 router has internal antenna which is not so good. Adding an external antenna significantly increased its range (approximately 3 times).
Please forgive the wiring mess in all my pics. My router is part of my home control system and there are some cables that are resident in that area. I tidied them up in this instructable!
Step 1: Solder Coax Cables.
My linksys wrt54g2 router had torx screws in the case. Using my "universal screw driver", I drilled open the case using my cordless drill of course. Why do manufacturers use those stupid torx? They shall not stop me from modding my router! Arghh!
Unfortunately my router does not have plug in coax connectors. I soldered the two female connectors to the board. The shield goes to ground and the inner conductor goes to the ANT solder point.
Step 2: Drill Case and Install Female Connectors.
Drilling an appropriate size hole and tightening properly, I now had easy to connect points for the external antennas.
Step 3: Add on the External Antennas.
I got a pair of - 9db antennas with the female connectors from Amazon. I screwed these on to my modified router. Powering Up revealed significantly stronger wifi signal and longer reach of my wifi.
Please note that the antennas I ordered are tuned for 2.4ghz. This frequency travels further than the 5ghz.
Step 4: Increasing the Range Further.
I raised router 3 feet higher to give some clearance from my pc case. I stuck it on the wall using velcro. The end result is my wifi range is 4 times longer than stock !
The other stuff you see in the pic are my imatic controller in the white pvc box and my labjack u3 to control the entire house. Yes yes I know the wiring looks like a mess but there is a method to that madness.