Write an iPhone and android application

Hi guys We have been working to design an app like "OOHLALA" (u can find it in iphone app store) it is an app for colleges and school to inform them about the activities going on in the school. We want to develop a similar app with same beautiful and clear UI. Please note a crucial difference in our app is that there is no chat option (which makes it somewhat easier) and revenue generation is through ad and it is free for user. We have details out the functioning requirement We want you to do UI design and make app for iphone and android in 2-3 months. Please give me a quote for that.