Don't think it is possible maybe using
http://www.dd-wrt.com/site/index
of course you will void your warranty and possibly brick your router.
I think if you call your ISP and ask them to add your MAC address. I have had to do this when I wanted to use my cable modem instead of theirs.
or you could just set ISP router to DMZ to your router and turn off all of their wireless stuff.
or it might have a bridged mode option.