Can I re enter United states with the same visa?

It is voided when the denial occurred - a new visa is required to re-enter. Contact a US immigration attorney for review.

1. Can I travel to my home country 2. Can I go for stamping with the extension receipt or I will need to wait for visa approval

Contact the company's US immigration attorney prior to any travel for status review.

The passport expiration does not affect your current status. You must renew the passport for future travel and visa issuance.

When is the time to file I-485/AOS for GC application

The day your PERM is filed is your priority date. If the PERM is approved, the company files the I140 and the AOS can be filed with the priority...

What is my status as per last action rule.

Contact a US immigration attorney to review the specifics. There may have been a period of unlawful status between your withdrawal and grant of H4.

What can I do to prevent him from becoming a citizen?

Contact a family attorney to review the specifics of your situation, most likely his "marriage" in Mexico is not valid. If he has had the green...

"Can I travel on my immigrant visa even though it will expire soon"?

You may travel freely within the US. Schedule an INFOPASS to get a stamped extension. Contact a US immigration attorney for assistance.

Should I ignore the letter or not?

Send the letter back and indicate you are not a US citizen.

What are my options. Could i eventually remarry and get my greencard that way. Is there a waiting period after the divorce?

Contact a US immigration attorney for specific review but at this time nothing can be filed for you while in the US without a US petitioner.

Will I be stopped each time and am I ok travel

It may remain in the system until you are a citizen.