Skn00b
there are many ways to get around mac address logging,the easiest is to delete the logs since the point is open the router password is probably default look up the default pass for that brand of router and your in. if you cant find the info on the internet try a combo of default, admin, pass and 12345 for user names and passwords.
you could also use a program to spoof you mac address, and there not hard to find if you can work the Google on the internet machine.