i140 number using A number from i797

[coolguyin2012]

Hi,

I have an Alien number from i797 after recent extension.

Can i get my i140 number based on Alien Number ? If possible how to get that ? 

I have applied for FOIA but it will take minimum 3-4 months.

I need to do a visa transfer, I don't have i140 number. If i specify A Number in petition, will i get extension for 3 years ? I have only 1.5 years remaining in my H1B visa .

I will appreciate if you can help me, I searched a lot but i cannot get any details.

Thanks,

Gokul