The best place for the wireless access point is the closest point to the users with the fewest solid obstructions (like walls) between the users and the wireless access point. You can also hookup via Ethernet Cable, another wireless access point in a different part of the house.
Having said that, location or even adding a second 802.11b/g wireless access point may or may not improve the situation. 802.11b/g uses spectrum that is unlicensed, and available for a variety of uses such as burglar alarm systems, cordless telephones, bar code scanners etc. The more common problem with Wi-Fi is interference from other users/applications, including other Wi-Fi networks in the area. That generally leaves you with only a couple of choices.
The first and the easiest is try putting the Wireless on a different channel. The router is generally set to automatic, however you can change the channel. The suggested non-overlapping channels are 1, 6 and 11. Your equipment will find the Wi-Fi signal no matter what channel it is on, if the signal is adequate. Channel selection is in the basic wireless settings under the wireless tab if you log into the router (at least for the Actiontec MI-424).
If that doesn't help, the next step (assuming your users are also equipped), is to buy a dual band Wireless N access point. and use it instead of the Wireless access point in your Verizon supplied router. Wireless N provides higher speeds, and operates in 2 bands, one is the same as existing Wi-Fi, the other in the 5Ghz band, where there is more 'real estate', and at least at the moment, relatively few users.
