This one is simple enough, to export your saved sessions and your settings for PuTTY, just navigate to the following key in the registry, select it, right click, select Export, give it a name, and save it somewhere.
HKCU\Software\SimonTatham\PuTTY
To import it, just navigate to and double click on your saved .reg file and answer yes to merge it with the registry.
If you need to restore the settings from a computer that is offline, check out my WinSCP post here and follow the same steps except substitute the registry key location.