Blocking A Wireless Area Network (WAN) Signal

Hey I was just wondering if any of you guys on here could give me some help with blocking or passwording a WAN I have at work. We are getting a lot of people around our mall accessing our WAN and our firewall thing is just going nuts because of it so if anyones knows how to either block the signal or password it I would be greatly appreciative. We are wanting to have remote access to it for the people that work in my store only but we don't have to have a signal so blocking is an ok option. Thanks.

Ok, ok, let me think.
If it's anything like my home router, if you access it's set-up (You can prob do this by typing in something like https://router - etc, not sure - you'll need to consult your manual I'm afraid, I'm sure it's nothing like my netgear one.
Well anyway, there should be an option in there to not broadcast it's name - then anyone searching for a wireless access point won't even see that it exists (I think). Other than that, you do have secure access set up don't you? So it needs a password and encription key. OK, stupid question, you obviously will

I'm no expert, someone will be along soon though I'm sure.

you can block a signal. you will have to password it, and secure it, but im not sure how thats done, you will need to check with the make of your wireless router thingy

Well from what I am seeing so far I need to find the manual. That sucks lol I am at work so it is going to be a bit of digging to get a hold of the manual they got with this thing. Also I know they haven't secured it like sheepy said because the guys I work with don't know crap about computers I am still dinking around with it and have done some things but having to find that manual is going to be the hardest part.