I was hoping to increase the range by around 20% would anyone know how hard this would be to change and what tools to use? Never modded this game before but I have some small experience in modding skyrim and other easy platforms.
First, you may want to give the modding guide a read:
http://www.grimdawn.com/guide/settings/modding.php
You would go to records/skills/playerclass05 and edit aetheray1.dbr. You would need to increase the maxRange value and the distanceProfile to Max on account of the longer range.