URGENT - Travel to India with pending/approved H1B


I am on H4 and filed for H1B this year, RFE is replied last month and now expecting approval in couple of weeks. I have to travel India by end of this month for some urgent work and I will be back in Jan 2013. My questions are 


 If H1B gets approved before I travel to India -

1) Is it mandatory to go for H1B stamping? Can I go for H4 stamping (my husband has changed employer this year so we both will be going for stamping)  and come back to USA on H4.

2) Can I file for change of status from H4 to H1B again after coming back to USA and start work once it is approved? or do I need to wait till Oct 2013?


 If I travel to India when H1B is in process -

1) What is the impact on the H1B process?

2) As told by attorney, it will abandon COS, but what about H1B? Will it also be canceled?

3) Can I file for COS H4 to H1B after returning from India on H4? or I need to file new H1B next year 2013?


Please mention if I have missed any other possible scenario here.

Please answer my queries asap, my travel plan is based on it.


Thanks a lot in advance.