EB2 timing

[bujjigadu]

I am working as onsite manager for an Indian service company (on L-1A vis) and will be completing 7 years in US in April 2012. My employer is willing to initiate my GC but is not feeling confident about putting me in EB1. If they initiate my GC processing in EB2 now, I have the following questions:
1. How long would it typically take for GC processing in EB2?
2. I believe there is no way I can file for extension of my L-1A and so unless my GC processing is complete by April 2012, I will have to leave the country, right?
3. What will happen to my GC processing if I leave the country in April 2012? Will it continue so I can come back to US once GC processing is complete?

Thank you so much for your response.

[txh1b]

1. Min 5-7 yrs
2. Yes unless you are on H1b.
3. Can continue.

[bujjigadu]

txh1b: Thank you very much for your response.
For #2, because I am already in my 7th year, I cannot shift to H1B now, right?
For #3, do I need to cross certain stage (for ex, I140 should be complete) before I leave USA for the processing to continue?