Mobile version of a Joomla site. Mobile App

I have a website that I want to have as an App in the Android Market, well, have it for Android/iOS to run on iPhone too. It is a simple website that enlists concerts and events in different cities, but if I can't make the mobile version work seamlessly I would like to know if developing an app is a cost effective way to make my website portable. The site allows registered users (via Joomla) to upload an event, date, time, place and images for the event. And to visitors, it allows the option to browse events, search by date, type of music, place, venue, etc. To see what is happening around town. I want to make the website portable, or else, I want to make the site into an app, whatever is more cost-effective.