Windows Server 2008 R2 Standard (non IIS) with Apache, how to setup mail?

Hello,

Just got a Windows Server 2008 R2 Standard (V-Server),
where i set up Apache/Mysql and Filezilla Server (FTP).
Not installed IIS.

Gone that way, because with "IIS" i never did something,
and heard for security, that apache is more stable.
All working fine, except for mail.

So now i need a mail server, and googled what
to do now, because i never set up a mail server.
I found out there exists "Mercury", and "Exchange".
So i asked the Hosting Company whats the best way.

They told "mercury" is slimmer for ressources than
"exchange", but "exchange" is the richer solution.
And i can install the "exchange" over the services snap-in.

Googled another one, and found an instuction:
(hxxp://(w)(w)(w).itsolutionskb.com/2008/11/installing-and-configuring-windows-server-2008-smtp-server/)
where it says to install smtp server. (But wheres "exchange"?)
If i would install smtp server, windows told, it needs "IIS".

So when i install "IIS" now.
Would my sites be still reachable?
Or can there occur some Ports conflicts,
or conflict with apache - IIS ?

Don't have installed "IIS" at moment,
i have fear nothing works anymore?

Is this the right way, on this instructions?
I don't know nothing about mailserver. :/
Could anybody please direct me in the right way?

Thanks for any help!

For the next persons which have the same problems,
i installed hmailserver on it. Whole install was a piece of cake.
Lets see, how hmailserver is working the next days, i hope good, also for security