With Urgon's part in your hand, try to get as near as possible to the ice monster, then hit the ctrl action key. This will hurt the monster, it will scream. Run away and retire (the right Aetherium indicator should disappear). Then repeat your attack. Do this three times as far as I remember, then the ice monster will die.
Make a F5 Quicksave after each of your attacks. As soon as the left health meter goes red, refresh your health with H.
Keep trying, good luck!