How can I re-position the search bar in the 'Superfish Menu' block? I would like for it to be centered and aligned all the way to the right (under the 'register' and 'login'). Is there any way to do this?

I'm assuming I have to either alter the PHP code, or CSS style sheet somewhere, but I'm not sure where. And, I'm not sure how to code for it. (I'm new to Drupal).

Any assistance would be much appreciated. Thank you.