Linux Extern Streaming

Run XBMC on my server in the TV room where I have all the movies, music and photos stored then I have a number of laptops and now even my Android phone as we also run XBMC on. These download media local network from my server and it works great but now I intend to take the step further and see if it would work to stream movies mainly when I'm on the go and want to access movies when I'm at the hotel.

Some more facts:

INTERNET:
Home: ADSL with dynamic IP (Telia) including Telia Smart Router
Travel: Hotels with Internet or at worst 3G/4G connectivity

COMPUTER:
Server: Ubuntu 4.12 + XBMC
Laptop: various types of Linux with XBMC ( two with Win7).
Phones: Android (Jellybean)

So I am want some advice how I can get it to work so I can access my XBMC server from outside my local network.