Clarification needed on L1B extension

[suthagar]

Hi,

I have my L1-B visa until March, 2020. I have got different dates for I-94, I-129S and PED as mentioned below:

I-94 and PED - Dec,2018.

I-129S - Feb, 2020.

I would like to know should I apply for an extension before my I-94 and PED of Dec, 2018, else Can I extend my I-94 by going out of the country and coming back to US and apply my extension before my I-129S gets expired on Feb, 2020.

Kindly put some light on this. Help is much appreciated.

Thanks in Advance.
Suthagar. S