Can I remain in the US on H1B approved June 2015 due to start work in Oct 2015

I am currently on H4 visa but luckily I got picked up for H1B lottery this year 2015 and approved. I am due to start in Oct 2015. Unfortunately my husband H1B primary has to travel back to India end of August. I know that on H4 I cannot continue in the US but since my H1 is approved can I legally stay back? Also I have a 4 yr old daughter, can I file for her H4 based on my H1B now or do I need to wait till October.

I don’t understand, is your husband going back for a short trip, in that case you are fine.

No. His assignment here is complete and ends 30th August. I can only start work from Oct 1st. I do not want to go back to India as I will have to go for H1 stamping to come back. Inbetween September we are not sure what to do? What can I do for me and my daughter to remain in the US?