I suggest you have a nice read through the wiki to understand how kodi works (and specially what repositories are). There is no more get addons in kodi isengard, you were probably running an older version in you older box. In isengard, get addons is the same as install from repository. You install repositories as zip files and you get addons from the repository (or better, install from repository). The only repository available by default (and supported in these forums as a general rule) is the official repositoy.
Also, kodi introduces changes to its database between versions. It is not a good policy to backup your userdata in one version and install the backup in a more recent version without expecting something not to work. It will most likely fail.
So, to be honest, configure kodi from scratch. You have done it before so you already now what you are doing. If you have some addon on the backup that you don't know how to find, just copy the addon folder + its dependencies + its addon_data/plugin.folder to the respective folders on the new box. Don't abuse of it, use only if you can't find something.
I have a strange feeling about your question so, its not bad to remind that this forum has rules and piracy or banned addons are not to be discussed nor supported in these forums ( read
http://kodi.wiki/view/Official:Forum_rul...ed_add-ons).
Good luck
