Provide two different networks with Internet while using a single ISP

Problem:
How to share a single Internet connection with 2 separate routers with both routers on a different network.  
I support a church that has a 25/25MB FIOS connection that they use for their office and business needs. Their network consists of a single SBS 2003 server with 16 workstations and 2 laptops. They have been running on a Linksys RV042 router for nearly 5 years with no problems and they has an exact backup RV042 that we’d like to use to provide wireless access for the different classes and groups that use the church at night during the week.
To completely cover the entire church we have 3 EnGenius Multifunction wirelesses AP’s that we ran CAT6 cable to from the RV042’s .
While we have been able to get the wireless network to work with one router the DHCP only running on the SBS2003, the problem has been that the laptops that connect wirelessly are receiving IP addresses from the server that are on the same network as the office systems and they would like for the public to receive IP addresses that are not on the same network as the office PCs.
When we use the two RV042 routers that provide two different networks (192.168.16.0/24 –office) and (192.168.1.0/24) for the wireless guests) It work fine until the DHCP service on the server would shutdown when it detected another DHCP service running and then the office PC’s started getting the wrong IPs. This also happened each time the server was rebooted the DHCP service would not start while DHCP was enabled on the second RV042.  
The RV042 labeled as “MAIN” is connected to a 24-port gigabit switch on port-1
The RV042 label as “WIFI” is connected to port-2 on the MAIN router and each of the 3 AP’s are directly connected to the WIFI router.  
I’ve tried using the different modes on the RV042 (Gateway and Router) and the DMZ port and every other cable configuration and yet can’t seem to get past this one.  
I was hoping to find a way to share the single Internet connection with two different routers without having to go to each church PC and enter a static IP and then disable DHCP on the server. It seems like this should be simple enough, though I have yet to find a solution.
How should we resolve providing two different networks with Internet while using a single ISP?  
Thank you!
Magothytech1Asked:
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TekServerCommented:
I think your best and easiest course of action would be to get the second router off of the main network.  This would require two things:  (1) ensure you have two or more public IP addresses from your ISP (if not an extra one shouldn't be more than $5 or $10 per month extra, at most), and (2) purchase a small 5-port switch (10/100 is fine).

Once you've done these two things, then you can connect the ISP connection to one port of the new switch, then connect each of the routers to another of the ports on the new switch.  Configure each router independently to get a public IP address from the ISP (no change should be required on the "MAIN" router).

No other changes should be required.  The three APs should be behind the "WIFI" router on one public IP address, and the business network is behind the "MAIN" router on the other public IP, completely separated.

Attached are a Visio diagram and two pictures (exported from the Visio diagram, in case you can't open it) showing my understanding of your current layout, and my above recommendations.

hth!
:)
Network.vsd
Old-Network.jpg
New-Network.jpg

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Magothytech1Author Commented:
Thank you Tek Server! I was hoping not to have to call Verizon and upgrade their service but after fooling around with this for several hours now I'm liking what you suggest here.

Will send them an email requesting that they contact Verizon and inquire on the costs of a second IP.

BTW: Nice drawings! What program do you use to create them?
TekServerCommented:
I used Microsoft Visio 2003 to create the drawings.  Highly recommended for network design (I believe the current version is either 2007 or 2010, and it comes with the fancier version of MS Office).  The "network.vsd" document attached above is the native Visio drawing.

You may get lucky with Verizon; they may already have multiple IP addresses.  Especially if they're on a business account; most ISP's business accounts start out including 5 IP addresses and go up from there.

:)
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Magothytech1Author Commented:
Thank you Tek Server!
Magothytech1Author Commented:
Nice Job - worked like a charm
TekServerCommented:
Thanks, glad I could help!

:)
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