After you log in to your word press account, go to edit your profile, it will take you to the global dashboard. Once you are in there, co to the dashboard button and find connections. In connections, go to add and manage applications. It will bring you to a screen that says Third Party Applications! I in the search bar, type upload plugins. then click on plugins.
Basically go to: http://en.support.wordpress.com/plugins
now make sure you have already created a profile and that your page is self hosted. If its just a word press.com, you might want to submit a request like what it says at the bottom of the page of the above link. but if your self-hosted…your good. create a profile, follow the above paragraph or go here:
http://en.support.wordpress.com/plugins/#plugin-requests
Click on this guide, located in the third paragraph, or
http://en.support.wordpress.com/moving-a-blog/#moving-to-wordpress-org, and follow the instructions.