L1A and H1B Validity

[mmoht]

Hello,

Following are my details

 

L1A Visa expiry : 31-Mar-2014

I-94 Validity : 18-May-2015

 

My I129 S Non-immigrant Petition

Date of intended employment 

Start Date : 31-Mar-2011

End Date : 31-Mar-2014

 

Company's I129 is valid indefinitely

 

My company is planning to apply for a H1B this year for me.

Till what time can I stay and work in US.

Is it till my VISA / individual I129 S  or is it till the I94 expires ( if I do not go outside the country)

 

And if I can work and stay till my I94 is valid when would my L1A status cease to exist assuming my company files a Change Of Status with the H1B application.

And the other question is if they apply from a green card will they be able to do it before the visa expires or I94 expires.

 

Any response is appreciated.