You can almost always extract more from your current employer (if you haven't been doing so), you just need to demonstrate the passion and will to do different things. If you do chances are you will get some more opportunities - if not then it really is a dead end and you should move on. The biggest mistake you can make at any job is to not learn or take away anything from it. Sometimes you just have to ask for what you want.

Jobs should be more than a paycheck. You exchange your time/effort for growing/learning. Both parties are aware of it and should act accordingly. If one party is not living up to the bargain it's time to find a new partner.