Is there an app to increse the ringer volume on my iphone?
I think there is any app that increases the ringer volume for iPhones called Volume Boost. It offers an incorporated music and volume control interface which provides you a level of control way beyond the usual limits of your device. You can get it at https://itunes.apple.com/us/app/volume-boost-free/id421816838?mt=8.
Don't think so... Sorry. :(