If you’d rather use a different tracking service, I’d suggest looking at Google Analytics or Piwik. Both solutions can be used via WordPress plugins like these:
https://wordpress.org/plugins/google-analytics-for-wordpress/
https://wordpress.org/plugins/wp-piwik/
None of these services offer an option to import stats from another service, though. I don’t think you’ll be able to import your historical data of Jetpack Stats (or another web analytics service) into another tracking service.
If you’d like, you can reconnect Jetpack to WordPress.com, and then use the WordPress.com Stats API to download reports of your data:
http://stats.wordpress.com/csv.php
http://phoxis.org/2011/04/24/wordpress-com-stats-api/
Once you’ve done so, you can deactivate the Jetpack plugin again, and you’ll have all your raw stats data available locally. You should then be able to create custom reports with a software like Microsoft Excel.
I hope this helps.
