Hi Gallo,
I found the learning curve pretty steep in that same exact situation. My final strategy was this:
Drop all the totems, move the four toons back, make sure that the main character gets the first CL and one frostshock out on the boss. Then, basically DPS down the adds and the boss. Keep an eye on the main character and heal early enough with lesser healing wave. I have on button that heals the focus (main) with all characters.

Here's how I did it:
http://warcraftmovies.com/movieview.php?id=62457

Hope this helps.