I am married to US citizen and we filled for change of status and we had our interview on april 10 /2012 and my case is still

We need more info about your case. I think the denial letter explained why USCIS denied your EAD application.

Which one usually comes first the EAD or the interview ( AOS through marriage to USC )?

It is case by case. It generally takes 3 months to issue an EAD.

PERM case in on OALJ, may I file 7yr. H1b extension?

We need more facts. Please consult with an attorney in private.

My Employer is starting the PERM Labor for GC. I have some questions regd. the minimum education required for PERM.

It depends on the employer's job requirements.

Going to my home countly for the very to get my H1B visa stamped.

I agree with my colleague. You might or might not need a new visa stamp. We need more facts.

My employer informed me that I received an audit on my PERM application.

1. USCIS issues RFEs. U.S. Dept. of Labor issues audits. They are different. 2. It is case by case. DOL deny the pending PERM application. 3. ...

How can I tell if I am eligible for the 17 month STEM extension

Your can download the list from here. http://www.ice.gov/sevis/stemlist.htm

Do I need to wait for H1B extension before switching job if my I-140 is approved?

Even if you switch your job, you potentially jeopardize your GC process.

1. You will be out of status. 2. You can not save your status by changing an employer.

GREEN CARD EMPLOYMENT BASED CATEGORY 3 (EB3)

No 2 years condition in your case. it takes somewhere between 3 months to over 1 year.