Convert MS ACCESS into web based Application

I have an MS ACCESS application that i built based on other desktop application made using .NET I built the MS ACCESS to give project winner better understanding of what i want to achieve. This MS ACCESS need to be rewritten into web-based application using PHP, JAVA, or maybe AJAX. This software will be used by cellphone store. So, you got to have good imagination of how the typical store run their business. This way you will know what their need : from purchasing goods, selling, receive payment, sales return, purchase return, managing stock, moving goods between warehouse, manage their employees and so on. All of this activity will need form to record the transactions and also corresponding reports to analyse activity. The important things about this web-based application : 1. It will need to run lightly especially when recording sales transaction as this application will need to get data from database (prefer mySQL) using internet connection. 2. It need to has the ability to read barcode and also make the barcode itself to be attached / taged in the items sold. 3. It will be need to calculate the value of the ending inventory using FIFO/LIFO/ or average-cost method. 4. It also will need to be able to receive data from swipe machine (something like membercard) to read the member ID or so 5. You have to know about how inventory system work, because this is the core issue of this application.