how to send data to and from an arduino to web server and database?

i have a project to do. i am to make a current meter and be able to access and send some commands to it through the internet like incase a pament is been made. i am using an arduino and an ethernet shield.
here is what i am looking for.... i am looking for someone to help me link the arduino and the database together (local host for the database), so that the server can get information from the arduino through the xml file that will be stored on the SD card on the arduino, and also the server should be able to send information to the xml file, in the case of a bill is been paid the server is to get that information from the database and send it to the arduino so as to enable the energy increased for that customer.
i am using a local host database.... please can you help?

i am using MySQL from wamp server
am using a SeeedStudio Non-Invasive AC Current Sensor (100A Max)
HR911105A Ethernet shield with the SD card on it
Arduino Uno

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