H1B petition validity after completion of L1B

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Hi I was in US on L1B for 4 and half years. In 2012 my company applied for H1B and I received approved petiotion with around 16 months validity. However I had to travel back in end of Jan 2013. I am getting another opportunity to go there. I have couple of questions -

1> If I go now, can I file for the extension for my stay in India ?

2> If I don't go and wait till Jan 2014 (1 year outside US) will it reset my clock and can I stay there for 6 years ?

3> If #3 is yes, do I need to file petition again ?

Please advice. Thanks !