Continue working for the same employer or change to a field of my interest?

Its been six months since i started working at this small company in DC area. The people are good, manager is good, the work isn’t I started as a fresher and my first priority is to learn as much as i can over money n anything else. I don’t get to learn as much new things as i expected and the job profile is different too(analyst-web development, sharepoint etc..) ? Now I have to decide and let my manager know if I want to continue with this company or look for a job in the field of my interest (networking) with a bigger company ? Could someone please help ?