Hi jaga_ps
to check what version of Vista you have do the following....
Right-click on Computer in the Start menu and click Properties to open the System Properties window.
Click the General tab to see the operating system version information.
To update Vista you will need an Internet connection. You could possibly use someone else's connection.
Another way may be to register with Microsoft Connect and see if you could download Vista Service Pack 1 ( which will have all the updates ) onto a CD or DVD and install it on your computer.
Check here...
Windows Vista SP1 Beta Program Extended– Microsoft Sending Out Invitations - Via Microsoft Connect - Softpedia
Hope this helps,
regards
Steve