There is easy way to migrate your customer base to your store. You can do so with the help of the free Import Customers app from the App Market:
- Install the Import Customers app in your store's account.
- Download the template of CSV import file.
- Using the template, create import file with your customers data in a text editor, for ex. Excel or OpenOffice.
- Upload the file to the app and it will automatically create new customers in your store account.
- You can leave "password" column empty. In this case we will generate a random password for each customer.
You'll find the installed app in your store's admin → My sales → Import Customers page.