Separate of account

Hi,

I have one business account in CRM 2013, but I need to separate it for 150 diffrent accounts. Im looking for the most effective way how to separate it. I can´t do this one by one. I tried to create new account by Temples for Data import, but it doesn´t work. 

Another problem is with adding 150 ISU numbers to 150 accounts.

Would you be so kind to help me?

Thank you.