請教小白免:opt EAD and h-4 question

Have a job now, opt will expire in May. I need to change it to H4 to keep my status since h1-b is not available( any idea about 2007 available time?).

If my company sponsor my h-1b, what is my option? ...I mean the time to quit my job in may or any suggestion?

If my company will not sponsor my h-1b, how long could I work or any suggestion?

I am in Nebraska service center.
Thank you so much.