Updating from 1.7 to 2.5

Can someone please tell me how to update my 1.7 Joomla site to 2.5 ?
How do I update the template? Is there a certain way to update the template?
Thanks

Hi,

Here you go official document from Joomla!: http://docs.joomla.org/Upgrading_from_a ... ng_version

Please notice:

- Backup total your site before upgrading.

- Restore/Install the backup to another place and try upgrading it first before applying to the live site.

- Make sure all customizations to the site are logged.

- If there are any problems, don't hesitate to ask me for help.

Cheers,