Applying for H4 while L1B petition is in process

[MadhuriHiregange]

HI,

I have the following query on my visa application.

I am currently awaiting my L1B visa approval from USCIS through premium processing. The petition was sent to USCIS on May 30th 2014. USCIS accepted the petition on June 3rd 2014. On June 6th 2014 my petition was moved to RFE.

How long does USCIS (under premium processing) take to respond once the supporting documents are submitted for RFE?

My husband is currently on H1B. Due to personal reasons I need to go there immediately. So can I apply for an H4 now? Will it affect my L1B visa processing in any way? If yes how? If it's possible to apply then what is the procedure?

Looking forward to your response.

Thank You!

Regards
Madhuri Hiregange