Know-How Exchange : E-Marketing

I currently use Constant Contact for a school. We are a bookstore on campus and have compiled our own list of students, alumnis, and staff. Recently we have had most of our email filtered into their ironport spam filter. The school is not willing to unblock Constant Contact IP or any outside 3rd party service, because that will open up to a lot of spam from other persons. They did say that if we have a server onsite, they can unblock that, because it will reside within our intranet, and they are willing to do that. What in-house software does anyone recommend? I did look at interspire(https://www.interspire.com/emailmarketer/), and it looks promising. Any other suggestions.