Do you mean you are thinking of switching to Axure ENTERPRISE? There are really only two flavors: RP and Enterprise. If you have "Axure Pro RP 7" or earlier, you should be able to upgrade to the latest version 8.1 for free. (The "Pro" designation was dropped in version RP 8 for some reason.)
If all you need is team project source files hosted on your own secure server, you don't need Enterprise. The basic RP version in 7 and later supports Team Projects for multiple authors, including placing the shared source file on your own server. That server just needs to have SVN installed.
You can find out more about how to set up your server to host Team Projects here:
The Enterprise version gives you all the benefits of Axure Share except the HTML prototypes are hosted on your own server (source, HTML, discussions, documentation specs, mobile Axure app, etc.) The Team Projects work pretty much the same though. The extra cost of Enterprise could still be worth it to you, though.
Either way, you're going to need someone in your IT department to install and configure software on your server.
The folks in email@example.com and firstname.lastname@example.org have been very helpful in explaining, demonstrating and troubleshooting all this. Hit them up with your questions directly.