EB3 to EB2: Different location, same employer

[trackerball]

1. My EB3 priority date is March 2004. I-485 was filed under EB3 in July 2007.
2. I switched to a new position which made me eligible for EB2 recently.
3. New Labor Cert filed in July 2012, got approved Nov 2012. New I-140 filed in Dec 2012 with a letter to honor the original 2004 priority date
4. Got approved by USCIS Jan '13 BUT they have the July 2012 date as priority date, instead of the March 2004 (they must have not read the letter).
5. Lawyers have sent a few letters, emails and phone calls to USCIS asking to correct the priority date. But has been nearly a month, and still no sign of correction.
6. Meanwhile, I have an internal relocation opportunity. Same employer different location.

Questions:

1. When am I eligible to move? Or do I need to wait till I have my I-485 is approved?
2. How long does the correction typically take?
Thanks

[abcdgc]

Is this company lawyer or did you hire this lawyer? Immigration lawyers have the reputation of deliberatly doing this to delay green card processing. This makes them more valueable for the employer. You should consider hiring your own lawyer to fix your priority date.