Partial restoration using J! 1.5 migration feature:
The first step is to backup only those database tables whose content you want to transfer to the new site. This can be performed though JoomlaPack. Start by using the table exclusion filter to exclude all database tables except the ones you want to keep. If all you need is the content, good candidates is the content and categories tables. Next up, perform a database only backup. The resulting SQL file is your migration data.
Full instructions here:
joomlapack.net/help-support-documentatio...eusingmigration.html