Automatically importing data from a website

I have a similiar issue as i need to add data from a website to my excel sheet every five minutes. the table can be reached through the following link:
http://www.excelforum.com/showthread.php?t=650275

http://www.fxstreet.com/rates-charts/exchange-rates/

how can i build such a query that adds the new data but not delete the old but to continue keeping it.

many thanks