sharing an internet connection, sorta?

[Fireradier]

I have an idea that I would like to try at my office.
I have a 30Meg connection on a dedicated static IP line that is hardly utilized, but does have important traffic on it at times. It's used as a SonicWall VPN link-in for field users to synchronize laptop data infrequently through the day.
As this connection is way under utilized I would like to use it for employee/guest access to the internet.
The internet connection comes from a Fiber-to-Wire connection box on the providers side into our SonicWall NSA E3500 appliance. Laptop users out in the city need a program and a key to get in to our network to synchronize data onto the servers.
What I want to do is put a WiFi Router between the two appliances that will pass the wandering laptop users straight through yet let the office staff link to the wireless and access the internet.
I just purchased a couple RT-N66W routers to play with. I updated both of them, then put Merlin on one and its doing just fine as a simple access point, but inside the network. I want it outside the network, on the 30Meg connection, as our internal network uses a measley 6Meg connection to the internet that it also shares as a dedicated data connection with our other location across town.
I guess my questions are:
1. Is this possible?
2. Is there a name for what I am trying to do? (what do I Google?)
3. Am I posting this in the right place? I read a bunch of very interesting and helpful posts about networking and the RT-N66 here but maybe this is more of a business network question?( I know the NSA E3500 isnt a typical home network appliance). In which case I would take constructive directions to a more appropriate forum.

Thanks for reading.

 

[theonlyski]

If you have more than one static IP address, then yes. It's do-able.

You would put a switch between the fiber ONU and the current E3500 appliance. One port going to each and a third port going to your Wi-Fi router. Assign the external static IP to the external of the Wi-Fi router and call it a day.

 

[Fireradier]

Well if its that easy.....
The fiber side has 4 static IPs, I think. Of which only one is used.
I also have a managed switch(HP Procurve) that might even have some empty plugs. If not I will break out the spare.
So to start I will want to set up the Switch with just the fiber side running straight through so that I know I wont upset the laptop users by jacking up their VPN tunnel. I am assuming with the managed switch I will still need to assign some kind of straight through pathway to that connection? So that the switch really just acts like a mid line connector?

 

[theonlyski]

Well if its that easy.....
The fiber side has 4 static IPs, I think. Of which only one is used.
I also have a managed switch(HP Procurve) that might even have some empty plugs. If not I will break out the spare.
So to start I will want to set up the Switch with just the fiber side running straight through so that I know I wont upset the laptop users by jacking up their VPN tunnel. I am assuming with the managed switch I will still need to assign some kind of straight through pathway to that connection? So that the switch really just acts like a mid line connector?

It would be best to have it's own switch, simply because it's less chance of cross bleeding the connections and virtually no chance an attacker would be able to hack the switch and have access to your internal network.