Sure its possible, but I'm not writing the guide on a step-by-step basis for your router.
You need to be able to know how to open your router ports to X (52199 is the default. look for "Port Fowarding" on your routers menu). You have to allow external access too for all firewalls you have/may have installed. Once you allow external access to JRiver media server (from the web), you can then stream it to your iphone/ipad by choosing "This Device" where you choose playback zones (on a phone thats on the bottom when you open settings; on an ipad its always visible, bottom left -- its sort of a circle within a circle icon.
As long as you know how to configure a router, its pretty easy. To use it as a controller on your local network you probably used the DHCP setting for your IP addresses already.
You might have to transcode on the fly to listen in your car though (you might have to stream in mp3 and not flac for example, depends on your bandwidth, internet connection etc.). A strong wifi in a bar handles flac for me no problem. Of course you have to have the machine running JRiver's media server on or at least "wake-up-able" for this to work
PS - you euh started a poll not a post??