Optimizing income of WhiteHat Android App

Hi, guys. Need your advice !

I'm about to experiment a bit with one of my Android apps.
Some info:
-It gets approx. 400 installs/day. Everyday it is used by 2k unique people. I monetize by AdMob (default banners/interstitials) and by purchasing "No Ads Product". It gets organic traffic without any promoting.

-AdMob gives me about 3-4$ per day which I consider is pretty low for this amount of people. No Ads makes not much too (90$/month).

-This app is very useful for people in one special niche. Can you give me a few ideas what can I change to make more money using that fact? Or using any other fact you suppose ?

Love you. Thanks in advance.

try tapjoy and for getting some extra goodies or power (in games) they have to use tapjoy video ads and earn rubbies that way you can earn more as you have 2k daily users

shahjee said:

try tapjoy and for getting some extra goodies or power (in games) they have to use tapjoy video ads and earn rubbies that way you can earn more as you have 2k daily users

Click to expand...

That is not the option in my case... All content in the app is free and won't be limited. My question is about monetizing the traffic in a specific niche.

try to use chartboost if your app is game ,or appnext also a good option !