Hi photolord, have a look here
Understandably, you don’t want to lose a single treasured reader. And, you’ll want to set up your subscription service for new subscribers to sign on first thing on your self-hosted blog.
Happily, the staff at WordPress.com will transfer your current subscribers from your WordPress.com blog to your new self-hosted site if you install the Jetpack Plugin by WordPress.com first. The Jetpack Plugin offers several handy features – mostly free and some paid – that you’re already accustomed to as a WordPress.com blogger. Free features include subscriptions, social media sharing, wordpress.com stats, spelling and grammar, a contact form, among others.
Installing the Jetpack plugin was one of the first steps I took after exporting my blog to the new site.
Install the Jetpack by WordPress.com plugin here:
Dashboard > Plugins > Add New > Search for Jetpack by WordPress.com and follow the installation instructions.
Once the Jetpack plugin is installed, contact WordPress.com staff and ask them to transfer your subscribers from your WordPress.com site to your new self-hosted blog. I was amazed by how quickly the staff responded. The transfer was complete in a matter of hours."
Haven't tried it myself so can't promise it works but would suggest you contact the wordpress.com support folks to clarify the if & how of this procedure.