Office networking difficultity

First question.... what is the difference between a switch and a router?

Can anyone please tell me if they see a problem or a probable problem with the following network structure?

Internet => Router1 => Web/FTP Server
=> Router2 => Mac & PC network

I want to protect the inner network with the least expense, I think a firework is enough to protect right now.

1.) How much is a web server software?
2.) How much is a FTP server software?
3.) I know that HACKING can't be stopped, but I just want a security where not just anyone can break though, so...is a router with a built-in firewall enough for the Mac & PC network to block out outer access?
4.) The ports 80 and 21 will be opened on the Router1 providing access on the FTP and WEB, should I use a a router or a switch on the Router2 location?

1, 2) Whatever you want to pay for it. Anything from free to $$$$$.

3, 4) Use two routers, arranged thusly:

Code:

---

        Inet
        |
        |
        |
        Rtr1
        |  |
 +------+  +-------+
 |                |
Rtr2            Server
 |
 |
 |
PCs

---

That assumes Router 1 is the sort with a built-in switch. If it's not, you'll need an extra switch to connect the two routers and the server.