After completing 5 year on Green Card, I filed for US Citizenship in May 2011. Priority date for my N400 application was May 31, 2011, and a month later I was fingerprinted on July 1, 2011. Since then I am waiting for a Citizenship interview and today 8 months have passed. USCIS website maintains a 5 months processing time for Dallas, TX center and I have been calling USCIS support center, only to be answered that I am within the normal processing time. On January 9, 2012 support center finally filed and e-Request and suggested that I should expect to receive a response from Dallas Center in 15 days. This time has also passed and I have not received any response.
I am worried, Is such a long processing delay normal? What are my option to expedite my case? Please help!
Thanks in advance.

