I got a single f1 visa and I have to defer to a later semester. what to do?

my clearnce date is august 17th , 2013 but my passport is not returned to me by the us consulate and my enrollment date has passed. so I have to defer my entrance to the spring semester. I hear that I have to go within 3 months to USA after getting a single student visa. So If I get a single f1 visa , what happens?


Change of status applied from B1 to F1. Could you please answer below points.

1.  Applied change of status , it came  to almost  90 days , but still status is in initial review ? what should i need to do? Do i need to consult immigration customer care?

2. My I 94 is going to expire in another 3 week ? Can i stay in USA after my I 94 expires ?

Please suggest me with your valuable advice.

Thanks a bunch