Hi there,
Not sure if you're still looking for shipping cost information from India. I also ran into the same problem with needing Java to view the India Post international shipping costs. But I discovered a workaround. Google brought me the following URL. It originally had South Africa in it. I just replaced it with U.S.A. and the weight with 20000 (for 20 kg) and came up with the amount in the results.
To get just surface rates, delete the "+air+lifted" from the URL. And similarly you can find out for shipping to other other countries.
http://www.indiapost.gov.in/Postage/...ed%2C%2C%2C%2C
Hope that helps!