Wired -> Wireless LAN migration

[alpha]

Looking for a little bit of networking advice following a recent house move. Pre-move, my setup was:

Internet --- Wired router --- FreeBSD server --- Wired switch --- Boxen

It was an awesome setup. NAT gave me the security I needed, and with port forwarding I had remote access to emails, VNC on each machine etc. The FreeBSD server does all kinds of things for the LAN, such as DNS, WWW caching proxy, IMAP, Samba and a ton of other stuff.

Now, I'm thinking drilling holes in the corner of the ceiling of each room in the new house and trailing ethernet cable across the loft and back into the room with the switch/server is annoying. If I could go wireless, it would save me some work and would be more practical. At the moment, I have a bodged setup which is far from ideal, just whilst I get my house in order:

Internet
|
Wireless router --- Box 1 (wireless USB dongle)
| (ethernet)
FreeBSD server --- Wired switch --- Box 2

This is because box 2 is in close proximity to the server and the switch (and has no means of wirelessness), whilst box 1 is on the other side of the house.

Is it possible to get a setup identical to the wired one at my previous house, except with wireless hardware? My guess was that all I needed was to replace the wired switch with a wireless switch and get a wireless card/dongle for each computer, thus:

Internet --- Wireless router --(ethernet)-- FreeBSD server --- Wireless switch --- Boxen

...or am I duplicating hardware here? Can I get the new wireless router to act like a wireless switch? It is the one sent to me by my new broadband provider, but it looks much more configurable and user-friendly than my old wired router.

One important aspect for me is NAT. I want NAT for security reasons. The examples above all only include two computers, but in reality there are several. I just need to finish unpacking.

Thinking about this, it might actually be quite simple but I've got so much on right now that even simple stuff is baffling me.