VISA possibilities for RN

I am a Indian nurse, Having valid RN with 7 years clinical experience, I have applied for green card through a USA health care agency. I got I-140 APPROVAL IN 2008.After that due to retrogression , my visa processing was stopped. Meanwhile i done my masters in nursing, now i came to USA on H4.

Is it possible for H1B for nurses/any way to work with my condition?
Is it possible to convert my EB3 case to EB2?