packet loss over the air will cause you to get lower speeds as you would with a cable connection.
if your just using the wireless for chat, web browsing and youtube etc then what you have is ok.
to make it better for yourself, go into the router web based user interface, and turn on mac filtering for every device you have connected over wireless.
at the same time, turn off your WEP security as you wont need it with mac address filtering on.
this will mean the router will only allow access to it over the wireless by the mac addresses that you specify.
this can help.
other than get rid of the belkin, this is all you can do.
i personally dont like belkin due to passed experiences. netgear is a personal home favorite, but i have not tried too many... ... other than cisco devices but you are looking at loads of money just for an access point.. and good luck configuring it without any prior cisco knowledge :S
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