Network concerns and configuration draft 4

Ok so here is the issue I have a desire to run my own linux server as an rt
box and to do wiki web serving plus email.

I run off of a qwest dsl setup that is feeding 4 computers that are all
getting internet in the following configuration

dsl non wireless model modem-switch-[a]windows xp home-[b]switch [same
model as other linksys switch from [a] --[c] linux--[d] windows xp pro--[e]
windows 2000 .

I will freely admit the following beforehand.

1. I just installed this network with the intention to share all the
computers in the house for dsl

2. My idea of what was a `router` `gateway` `switch` was initially sketchy
at best.

3. I checked the intewrnwet beforehand and tried to setup "advanced port
forwarding" with all the ports did initially 80 from the router control
system failed to work.

4 it seems that it was working for a while in my internal network under
dyndns but it failed when testing on a work web browser.

5. dyndns didn`t work as the machine didn`t route the traffic out of my home
even when directly ordered to by the dsl router-machines on the inside could
though

6. I am looking for the best option for the money I like cheap and I like
something that gives all comps access but allows me my file serving.

So I guess the issues I need fixed are

1. historically getting past qwest DSL Router into the network would be
required. Not just standard in/out internet traffic.

2. what specific hardware and cheapest ingredients [if any] I need to get
past both switches and onto the internet

3. would confusion of switch==router historically be a problem?

4. would getting past the password protection on the router be very hard?
[this was a concern when my dyn dns kept hitting an open config page