I figured as much, sorry if I offended you when I asked as to why you have so many routers and switches, it is just that I don't normally see so many of them in a network so small, I mean I have 1 router for 7 computers, and that works very well.
I also took a quick look at your modem's specs, it does not specifically state that it accepts more than 1 IP address (or at least I did not see it). I see that it says it can handle 32 users (31 via ethernet and 1 via usb) but I am not sure if that means that I will get and distribute 2 IP addresses.
I am not sure why you would not be gettin 2 IP addresses if the modem was able to. Maybe somebody else could help.