Right, but I'm trying to get a feel for how your content is inserted. It was a little confusing, as you have some links going to .html files, etc. Your archive for the news section is here:
http://kondwani.com/stamp/category/news/
But your news archive link for February 2011 is linking to here:
http://kondwani.com/stamp/2011/02/
which is supposed to be the archive for the entire site - it's not "news" specific. But your "news" stuff should be in there - but you're right, it's going to the index page.
Does your index.php have a layout for the archives? or do you have an archive.php template file in your theme? The category listing is showing up fine, so that tells me you have something for perhaps a specific category setup, but probably you don't have a default archive setup - save the index.php file. If your index.php file doesn't have an archive-specific loop, and you don't have an archive.php file, then it's just going to show the index page.