invoice/billing

I require an invoice and billing system for milk delivery, we have a web site which is in the process of being built Please find below the list of Phase 1 and Essential Requirements we need to have it as a base. Phase 1 Public View *********** - As a public/new user one can view the Products list along with Price, Description and Image. - Place Order or Buy the desired products (Ordering Method) -> As a regular user registering and placing an order. -> As a guest user register and buy product online. - Can view content Pages like About and Contact. Super Admin (Site Owner) ************************ (Master Screens) - Add/Edit/Delete Products - Discount Option while adding a product - Add/Edit/Delete Category - Provide Company Information like Name, Address, Phone, Fax, Email - Areas we serve (Postal Codes) - Customer/Contact Management (Customer listing, Approve option) (Transaction Screens) - View Customer Orders, Modify Orders - Create Invoice and set the due dates - Reports - View total Sales by monthly/yearly, View Outstanding Dues Customer View ************* - Register in the system - Places an Order, Change or Modify Order - Reports (List of orders placed, Invoice list & Pay Now button) Email Notifications ******************* - At the time of invoice created (Sent to Consumer) - When there is Outstanding dues intimation to Consumer and Admin - When an Order is modified by the consumer notification to Admin We have a bunch of value added ideas but it keeps expanding the scope. Let us take one after the other. Thanks & Regards Frank