Indeed, a final return should be completed for the period ending 12/31/2011.
That final return should indicate zero on all of the balance sheet items including disposition either by sale, trashing or distribution to the shareholder of the assets.
You did not mention the state in which you were incorporated; but notifying the department of state is highly advisable. Some states, like California, will continue to charge the corporation unless notification is made and others will simply dissolve the corporation when the annual fee is not paid, like Florida; but it still is proper to file the notice of dissolution.
As the sole owner of the LLC you may need to change or file new form W-9 so that customers or clients have the correct taxpayer identification number and entity status.
As the sole owner of the LLC you will now file the proper schedule on your individual return for the activity: Schedule C for business, Schedule E for rental, Schedule F for farming, etc.
Please ask if you need clarification.