Build an Online Store

We need website similar to http://www.perfectofficeaids. com/ and [login to view URL] We require additional facility for our Corporate and Institution customers. Some of the points to be taken care of are: For our Corporate clients (As every client is likely to have different rate and items as approved) we require the following. 1. Login ID /User ID for the client. 2. Login ID/User ID for clients approving authorities. 3. List of items as approved by the client along with the image, rate per item , quantity ordered , total value (rate x quantity) 4. Tracking facility of the order for the client using order id 5. They should be able to raise the order without making the payment as most clients are supplied on credit basis. 6. Notification / alert of client order sent to us in email and mobile sms. Kindly indicate the cost.