Travel to U.S. while H-4 to H-1 is in process

[immihelp]

Sir/Madam,

I am working here on H1B in US based company.
My wife is staying here as my dependent on H4 visa.
She currently doesn't have most recent valid H4 visa stamp in her passport as she didn't travel outside US since her most recent H4 Petition got approaved.
She is planning to travel India for 4-6 Months.While coming back to US she will have to get H4 visa stamp at India based US Consulate.
While she is in India, can US based employer file for her H1B once the visa becomes available for the year of 2007-2008 in April 2007, when she is in India?
While her H1B application is in process,can she travel back to US after getting H4 visa stamp on the bases of her current valid H4 petition before the decision is made on her new H1B petition?
In case if the decision is made on her new H1B petition while she is in India ,can she still come backon H4 visa before October 2007 as she will not be able to start her work till 1st October,2007 on the bases of new H1B?

Thanks

[immihelp]

Yes to all questions.