Hello there!,
If you agree/want, I'd suggest (because we use something like this where I work), the whole solution is made in Java, with JSP for frontend, Servlets for backend and server Tomcat7, also, we use Amazon S.E.S to send the emails (if you send lots of emails from a simple and common email, it could be blackmailed, or even blocked depending on the provider), it's too simple for now, you upload an XLS file with the addresses, we have our mail templates (HTML) stored in a directory, and we pick the right template according to the XLS file name. All of this hosted in an AWS EC2 instance.
But, what else do you need? would it be enough with just a simple page where you can write the subject and load the list of emails?, nothing else? no DB for tracking, for history, no nothing?
I'd like to talk with you about it, since I think it could change the costs of it (or add monthly costs to you :P).