How to select and reflect the latest details of a customer

Hi, I am helping a business to develop a system which can easily allow the staff to find customer data and input new details of payment. I've attached an excel sheet of the data for easier reference.

I would really appreciate help for the following:

1. A searchable drop-down list for to find a customer's name in B3

2. When I select a name from the drop-down list in B3, the latest Treatment Date for that customer should be reflected in B4. Then, based on the row of data with the customer's name and latest Treatment Date, the corresponding values for Total Package Price, and Balance amt unpaid (in purple) should be reflected. Meaning, I want the system to reflect the row of values based on Alice's visit on 13-Jun-13 instead of 6-Mar-13.

3. I will then input data for Treatments done today (orange cell) and when I click the Enter button, the data in cells B3, B5 (because I want to record today's payment), B6, B7, B8 should be added as a new row of data according to their respective columns D to H.

I'm still new to excel and have very basic understanding of excel and macros, so I'll really appreciate it if you could take me through the steps one at a time.

Your help will greatly allow me to understand excel functions better and contribute to a business, thank you so much in advance!