Need Help I-94 Renewal

[niceguy534]

Hi Friends,

When i entered USA my passport expiry date is May-2012 and my H1B visa expiry date is Feb-2014.

So officer verifed the above dates and given me the i-94 with expiry date as May-2012 as per my passport expiry date.

Now i got my renewed passport and i need get a new I-94.

So i am planning to go Mexico for getting a new I-94 according to my visa expiry date.

I have the below question .can you please answer.

What is the best time to travel to Mexico, Is it required to travle just before 1 day of i-94 expiry date? or i can travel immediately?

Where should i submit my old I-94 while going to Mexico or when coming back to US?

What are all the question i face when going to Mexico/returning to USA?

I heard that trip should be 30 days to submit the I-94 , what if i stay only for 2 days in Mexico. Will they not give new I-94?

Please help me