Create a Mobile Website

To design a web based app that can be accessible via cellphones, laptop, PC'S and tablets via a login username and password. This app must pick information through the use of a couple of drop down menus from a database that will be updated once a month using excel spreadsheets and/or. Csv files (whichever works best for us) In a nutshell taking large spreadsheets, virtualising it in order to access specific data on demand and making this accessible to people on the road. I need a prototype ASAP (which I am willing to pay for) to sell the idea afterwhich I would like to work with the same developer (if still interested) on a full time salary basis.