221g and renew of I-797


I had received 221g from consulate A as i was not having client letter and later my company has done amendment with change of client and location. I had received 221g again saying that additional administrative processing is required. My I-797B is valid till 19-Nov-2017 only. How much time it will take to process the 221 (g) and update it to stamped. If administrative processing is not finished within validity of my I-797 and if i renew this, will it create any problem in future for stamping. What is the additional care required to make it through next time.

Please reply.

Thanks and regards