Here is a software which does exactly the same thing which you want. [url]http://www.shaplus.com/exes/misc/DataOne-Bandwidth%202.7.zip[/url]

below are it features:
"New featues in 2.7
Changes in Summary tab - New fields 'Average usable' and 'Average used' excluding today. (These fields are displayed only if 'Last Recorded Date' is today.
No need to have MS Office installed to display chart. (chart using MS Office still retained)
Export data to csv format (can be opened in applications like Excel)
List of different dataone admin URL can be stored.
New featues in 2.6
Supports revised plans introduced by BSNL from Jan 2007 onwards
Interface changes to check usage for 6 months
New featues in 2.5
Average and Total value display in chart.
New summary section, displays average used per day , average usable for remaining days, compare your bandwidth in different other plans, estimated bill etc.
Compare total bandwidth displayed in dataone site with total of all rows to ensure that all rows has been retrieved. (It has been reported that sometimes (may be rarely), some rows are missing in log displayed at dataone site, which can result in incorrect report)
Those who do not have night unlimited, can turn off splitting usage into free and non free.
In password version, background processing while retrieving pages from dataone site is shown.
New featues in 2.4
Daily total for charged and free usage
Corrected bug - not displaying freeusage correctly, when there is mixed usage.
New featues in 2.3
Exact charged bandwidth is shown, if free usage is excluded(making use of new column in dataone website showing "traffic excluding night unlimited")
Bug fix in 2.2
Fixed a bug causing it to not function in 2006. All older versions will not work anymore.
Bug fix in 2.1
Fixed a bug causing this to not work in some login URLs of dataone admin site. If previous version of this tool was working fine, no need to update.
New features in 2.0(07th Nov 2005)
Chart display for daily usage
Displays Free,Mixed,NonFree rows in different colours(Customisable - Left click to set font color, right click to set row colour)
Display of Report using Cache data (If "Retrieve only newer records" is enabled previously)
Report screen is now resizable, so can display more records in larger screens
Bug fix in 1.3.1 (21th oct 2005)
Sessions overlapping both ends of free period was not included in mixed usage list. This is now corrected.
Changes in 1.3 (17th oct 2005)
Daily total display
Option to retrieve only newer records. Saves lot of bandwidth if you check usage often and your log runs into many pages.
Reports can now be saved
Added a Nonpassword version for those who are not willing to enter the password into this tool"