Would it be possible to talk to your 'boss' and say something like 'I am so grateful to have this position and opportunity, etc. I feel I am ready for new challenges. Would it be possible for me to spend some of my work time on (fill in the blank with what you hoped to be doing) to further to further expand my learning?' If the boss says yes, then pin it down as to when and how your role will change so it isn't just talk with no action.