You can always add additional .csv files.
From the right navigation menu, navigate to and click on "Add new data source". You'll go through all the same options as during the phase.
If you want to import personal contact data (e.g., phones and e-mails) you have in a file, without affecting the status of existing leads, during the import phase, do not specify any mapping for the status column, and when asked to provide a default status, do not specify any. That way, no statuses will be changed, and your additional data will be imported and avialble for you in Lead Profiles and for export to your CRM.
