I'm an experienced developer (over 15 years, mostly on java) and I've been working on iPhone and Android apps for over five years. I developed many app you'll find on App Store and Google Play, please take a look to my website for details: www.tapcoder.com.
I'm available to start working on your project right away and you'll always find me connected to gtalk and Skype.
Regarding effort required to complete this app, I need more information to give you an accurate estimation.
Regards,
Sebastian