Updating to Joomla 2.5 from 1.5.22 in

Hello,
I am on 1.5.22 (Restaurant template) and want to update to joomla 2.5 on both my Restaurant & Hot Destination templates.
Do I have to update first from 1.5 to the next one and then the next update etc or can I go directly from 1.5.xx to 2.5?
Will all my site content update automatically to the new version?
Before updating, do I have to do anything w/my host to make sure the updated version of joomla works on their side?
Thanks for the assistance!
Patsy

Here is general page about that:

docs.joomla.org/Migrating_from_Joomla_1.5_to_Joomla_2.5

we have 2.5 version of template, first go with joomla update so db and core files would get updated. Then install template we created for 2.5. This also counts for our modules.

be prepared to knock your head few days to fix everything

LOL Thanks!