uhh...
well you have to open up the setting page in your internet explorer.
check out the page
www.portforward.com
just look under the router section and look at your own router and see how to change the settings.
when u get into the settings page there will be a section called wireless security, when u get into that section there will be an option called WEP and WPA... choose the WPA one and give in a password, and then it will ask for your password once and it will be secure.