NAS Drive through Ethernet Switch

Hey, guys.

I have an external hard drive that's been sitting around my house for a year or so, so I wanted to make something useful out of it. It's an 'iomega', and I'm guessing it's 500gb or 1tb. I really don't know anything about NAS drives or how they work, but I was looking up a lot today and figured a few things out. There was one thing I wasn't able to find, however, and was wondering if someone could answer. I have a my an ethernet switch that's connected to my printer, computer, and modem. Could I plug the NAS drive into the ethernet switch? Is there some sort of program I could use, or is it just not possible? The problem is, I've used all 4 ethernet spots on my modem.