Hi Leena Jain,
I've a couple of suggestions. Yahoo have a webservice you can use, but you might want to check the terms and conditions. Here is a sample calling the API. If you can't use the Yahoo webservice then the sample should get you started calling any webservice returning a JSON result. https://sites.google.com/site/livecycledesignercookbooks/home/YahooAPI.pdf?attredirects=0&d=1
(there are probably more currencies supported by Yahoo, I've only loaded a sample into the drop down controls)
Another option would be to load a xml file from a webserver, this sample loads the European Central Bank file they produce after each trading day.
https://sites.google.com/site/livecycledesignercookbooks/home/European%20Central%20Bank.pdf?attredir...
(I don't believe there is any restrictions on accessing this file, but it only includes a subset of currencies ... still this sample would be easily modified to handle your own xml file) ... check the preOpen event.
(Both samples might give you warning messages depending on your installation configuration, but offer the "Don't ask again" option.
Regards
Bruce