No need to login everytime to see how much you have downloaded.Its easy.Install this firefox plugin.

DataFox is really easy to use. Once installed, you should see this icon () in your status bar. Click it to bring up the login dialog. Select your ISP, then enter your name and password and click the Login button; that's it. Click the icon again to refresh the usage data.

DataFox works by obtaining usage information directly from the BSNL / MTNL usage site, it does not monitor your network in any way, so usage details probably won't change until you logout of DataOne / TriBand and log back in again.