Optin system

I have a server with hosting and cpanelx. I require a simple optin system and email database so I can have an optin box on my site(s) with subscribe/unsubscribe and autoresponder function and a way of designing and/or maintaining the optin box itself. I also need the ability to set up additional campaigns later on, so the system must be replicable. At this time I have a bulk email package (Email Marketing PRO) that allows me to send out my newsletters to my list. It allows me to import csv or tab delimited lists, so I wish to be able to use this in conjunction with the optin system, unless you have a better suggestion. I am NOT interested in "Aweber" or any of those other optin schemes that require a monthly fee. I would however, be willing to look at any "package" that I can pay a one-off fee for. But it would be preferable to have my OWN system. So, just to be clear, I want to: a) Be able to create an optin box with associated autoresponder confirmation/success messages b) Place it on my site (I know how to embed code) c) Have the subscribers added to an email list on my server d) Use my marketing package in conjunction with this list to send out my newsletters. e) Set up another campaign if I need it later on