How to set up both static and DHCP assigned addresses on an AirPort Extreme

Question

I recently bought an AirPort Extreme to replace my failed Cisco/Linksys router.
I am having trouble figuring out how I can configure the Extreme to support the already static IP addresses on my network as well as assign IP addresses via DHCP to a few devices where static IPs are not supported, i.e., work laptop.
Additionally, when DHCP is turned on, are my only options the 10.0, 172.16, and 192.168? What if I am running something like 10.10 or 172.30?
I am far from green when setting up computer networks, but this AirPort Extreme is making me pull my hair out.
BTW, I have access to a number of computers running a number of OSes including Windows XP, 7, and 8, as well as Mac OS X Snow Leopard and Mountain Lion.
The Mountain Lion or Windows 7 machine would be the preferred ones to configure the Extreme. I already have the AirPort Utility software running on them.
Any help would be appreciated.

Answer 1

I have found the 'DHCP Reservations' option on the AirPort Extreme to be buggy.  I seem to remember it causing IP conflicts for some reason.  I think what I remember is that if the computer with the reservation was off, and the DHCP server then handed out that IP to another DHCP client, then there would be a conflict when the reserved IP computer was turned back on.  Maybe it was an issue in ealier versions of the AE or OS X as the case may be, and maybe it's been corrected, but I've never bothered using it agian since the method I describe below has always worked without fail.  Also, I'm guessing DHCP Reservations would work fine if one manually enters IPs outside of the DHCP range but in the AE 'DHCP Reservation Setup Assistant' the IP options provided are within the DHCP range which to me makes no sense and increases the potential for IP conflicts.
Here's what I do to setup a mixed environment of static and dynamic IPs on my network.  It works like a charm and does not require the DHCP server (beyond the distribution of dynamic IPs to hosts using DHCP).
For machines on my network that are accepting services from the public network, I set them up with static IPs using the 'Manually' option (System Preferences/Network/Ethernet/Configure IPv4).  The settings for 'Router' IP address and 'DNS Server' IP address should both be set with your gateway/router LAN IP).  Use an IP address below or above the DHCP range of adresses (in AE/Internet/DHCP/DHCP Beginning & Ending Address).
i.e. if my subnet is 10.0.1.1 and my DHCP range is 10.0.1.100 to 10.0.1.150, you could set the static IPs on your local hosts as 10.0.1.x where x = any number from 2 - 99 or from 151 - 200 as an example.
All other machines and devices that do not require static routing are setup as DHCP clients and get a dynamic IP from the AE.  To me it's a simpler setup though it might take a little extra time to setup initially.
John