H1b, EAD - need advise

[Krantikari]

I worked on H1b for 4 years (my GC was w PD of May 09) w previous employer

and moved to another state on EAD through spouse (Current PD is May 09 as well) 

However, I am trying to explore options to return to my previous employer 

a) Can I work on current EAD (if my spouse doesn't revoke it), OR   Do I file for H1b (2 years left from prior work) 

b) Can I make use of my prior GC application (I 140 was approved there as well and I was waiting for PD to be current)  If so what is the procedure for this?

Thank you.,