this post http://forum.mikrotik.com/t/exporting-dudes-http-graphs-and-charts-with-curl/48675/1 has details of a curl script that will automatically get graphs and charts from The Dude webpage. Part of the process is auto authentication which (from memory) involves manually authenticating once and then doing something tricky with a cookie. I did set this up at one stage and had it working, but no longer have the need for it.