Write an Android application

I need to create a small in-house web portal. More like a single page application (gmail kind). I have three masters - Customer Database (Name, Contact, Email, Price level, Account Balance, Notes), Vehicle Database (Model, Make, Year, Vin#, Plate#, Color, Owner - Select from customer database) Price list (Part#, Name, Qty, Type, Retail Price) And a Work Flow System. We create tasks called 'Files'. A file has four elements - Lead, Sale, Job, Invoice Lead - File number (Auto), Customer (From Master), vehicle (From Master), Observation (Text area), Case (Text area), Mileage (Text box), Expected Delivery date. Save and Edit Sale - Add parts from price list and calculate total value. Here there is a button called Estimate (creates a pdf format of Lead and Sale) in a unique link. Job - something like feed. users type in short messages and feed here. Cannot be edited or deleted. Invoice - the total of invoice is put and amount is paid. (No invoicing - just for information) Dashboard - shows the list of all files.