email marketing to prospects, not subscribers

[thesaintv12]

All of my email marketing so far has been to opt-in subscribers via aweber.

As part of another venture I want to email prospects who have contacted us to inquire about our services.  However, I don't just want to send a newsletter, I want to use an auto responder similar to aweber so that I can improve the offer (or the price) as time goes on. 

I also need to be able to view which was the most recent message, so that I can know what the offer they received was.

Does anyone else do this, and if so how do you do it and what do you use?

I can't use aweber as they need the recipients to confirm subscription, which they have not because they contacted us out of the blue.

[thesaintv12]

Ignore the above, it seems I can do it within aweber.