Applying H1B extension with change in role

I am an H1B visa holder trying to extend the I-94 going through a tough situation. Greatly appreciated if any one can answer my question’s.

Current Situation

a) I-94 expires on Dec-3-2013

b) I have now change in my role to accommodate the Prevailing wage

Questions

  1. Does my employer need to file a new LCA ?

  2. How long is that going to take ?

  3. Does this new LCA need to be published ?

  4. Is there any possibility of rejection ?

  5. Any other best ways at this situation ?

Thank you very much for your time and help!