marriage GC interview, 863211 please

Dear 863211:
I went to the marriage green card interview yesterday. Everything went pretty well. I filed I-485 with my previous employer before, so the interviewer said that they have to order that file from Nebraska and then she will mail me the Approval Notice. Sounds like I passed. Do you by any chance know that how long the ordering file from another location is going to take? Is this just a normal immigration procedure, and there is nothing to worry about?
She also took my original I-94, shall I go get it back? I think I will need it to leave this country next time, am I right?

Thanks