Currency Exchange Rates Feed Processing

We need a php script developed that will be run as a cron job to populate our exchange rates table. We need the script to provide the excahgne rate for all global currencies against US$, GB£, Euro, CN$, AU$ and JP Yen. We also need a one-off script developed to populate out currency table with the available global currencies. I have attached our table layouts. We are looking to achive this without paying for a currency feed and want to begin immediaiately. Thanks