Assuming you pre-ordered and are allowed early game access you need to uninstall the beta client and download the game client. Once you have uninstalled the beta client through add/remove programs then log into 'My Account' on the top of the webpage here at swtor and the click 'Pre-order' button under 'Account Management' and then click the 'Download Game Client' button to begin downloading it.

Easier to deal with keeping their Facebook page open to see updates. http://www.facebook.com/starwarstheoldrepublic