According to this the G604T is a stand alone device. It has the ADSL modem, hard wire ports, and wireless built in.
> Take one of the laptop's and hardwire in to the router. Log in to the settings and make sure it's set up correctly. Out of box doesn't always work like you want it to.
> Check for interference. Any device between the wireless base and the laptop that is cutting out is suspect. Microwave ovens, cordless phones, even bluetooth headsets can interfere with the signal.
> Check the position of the laptop. The built in antenna system is directional. Try moving it to different positions in relation to the wireless base station.
Also keep in mind that indoors the signal will not travel as far as it would outdoors.
> Change channels on the wireless. Could be some one close by has wireless also. Being on the same channel can cause some forms of interferance.
Ok having check everything and still having problems, you could resort to an access point. It plugs in to one of the hardwire ports on the router. You would log in to it and set it for AP mode and set the channel. Then set it on top of the highest piece of furniture or mount it to the top of a common wall.
I use the TP-Link access point / repeaters. Less than 30 dollars US and worth every penny.