1.just open the web interface for modem/router config.
http://192.168.1.1
(By Lan not Wlan)
2.advanced setup
3.WAN
4.edit the entry with vpi/vci 0/35
dont change anything else in the settings
just click next next till you get ppp username,ppp password like fields
5.once you get it enter your broadband username and password here
authentication should be set to AUTO.
6.enable wireless from wireless section
7.save setttings and reboot
thats it now u should be able to access WLAN
NOTE :: c ur internet becomes ALWAYS ON because of these settings.
username/ passwords of your router to change the settings can be- admin/admin.
or defined in router manual.
Source: googled it.