H1 extension after I140 is approved

Hi,

I am with company A on H1 for the past 3 years and i have GC I140 approved with this company. I have the soft copy as well with me . I was on L1 for 1.5 years with other company and on H1 from 3 years onwards with this company A. So overall , i completed 4.7 years in US. If i switch to other company B now with H1B transfer by showing approved I140 , I may get H1 validity for upto 2 years. The question is , Will i get H1 extension again with company B if i apply for extension with company A approved I140 or i will not get extension? Please clarify me on this. Also, Let me know what will happen if company A withdraws my GC I140 after i quit ?

Thanks

Basu