This is a very simple Web Site security features project. You have to add few features in it.
1- Log On and Log Off record with EST(eastern standard time) or any other default time specific for that region.
2- IP address record
3- Auto Log Off after fixed time (5 minutes or 10 minutes) if user is not active.
4- If auto Log Off than log on to that page where user was already working.
Please chech the attached file to get the better idea.