Hi,
Mmm. If it were on the same website, just running the import again would just pick the new data and leave alone the data already migrated.
For the users, you have Joomla tools to export/import them, so that should not be a problem.
For the user's addresses and orders, if you still have the old HikaShop you used for the first migration, you can run the import again. That will get the new orders/users/addresses in HikaShop. Then, you can simply delete the tables of these (order, order_product, user, address) on the new website and get them from the old website. Hopefully it should work.
Otherwise, the best solution is to run some custom and complex MySQL queries to port the new data from the old website to the new one. If you know pretty well MySQL, that might be the best. Otherwise, I wouldn't recommend it.