Question: Help me complete this network.

I have a cable modem going to a switch. The switch has various devices connected to it. A few computers and a wireless router. I have a a number of computers connected to the wireless router wirelessly. 

The devices connected to the switch together can communicate with each other. The devices connected wirelessly to the router can communicate with each other. But the wireless router devices can not communicate with the wired switch devices.

How do I make this one larger network?

Answer: 
I suggest you use your Access Point as the main router/firewall between the modem and the switch:

Modem>AccessPoint>Switch>Clients ('Wired clients' connect to switch, 'Wireless clients' connect to Access Point through it's SSID. The Access Point will serve addresses via it's DHCP service to all your clients). This configuration will keep your inside clients safer and on the same network.

By the way, this probably belongs in superuser.com since sounds like this is a personal network.
I agree with l0c0b0x. Also both the modem and the wireless router are probably running DHCP servers. You will want to turn one of them off, usually the easiest one to turn off is the one on the modem as not all wireless routers let you turn DHCP off.