basic server question

[Eric]

Given the following configuration, how many static IP addresses will I need?
I have one static; is there a mechanism (NAT?) whereby I can set up the
following network with only one static IP?


I have a cisco 675 DSL router, which goes to a zonealarm firewall until i
get the knowledge to configure linux box as a firewall, and the cajones to
trust my data with it.

Whichever firewall is used, I want host my own site on Apache Web Server,
and also host some type of e-mail server.  Lastly, I would like to set up an
SSH server, and create a VPN between home and work.

Is one IP address sufficient for this, or do I need to pay qworst even more
money?  Could you explain?  Thanks very much,

eric