Need Help on 6 years stay in USA

[roopam]

Hi
Can someone please help me on my query asap.

I came to USA in April 14, 2008 on L1B visa. I was in USA for complete 3 years period (except the vacation time around 30days) + 240days during L1B my extension. Total stay in USA is 3.8 yrs and then left to my home country due to my L1B extension denial (L1B issue/entry date: 24Mar2008/14Apr2008; L1B expiration date: 17Mar2011; L1B extension period: 17Mar2011 to 26Nov2011).

My company filed H1B for me when i go back to India which got approved for the period of 12Mar2012 to 15Dec2014. Using my H1B i have re-entered in USA on 15Sept2012.

I need clarification on below queries, please help.

1. Is the 6 years stay in USA only applicable for H1B visa? or
2. Is the 6years stay in USA considers my stay of both L1 & H1? If yes, can i stay in USA beyond 15Dec2014 (by applying H1B extension) as i was out of USA for 10 months during 14Apr2008 to 15Dec2014 period.
3. Any other ways to stay in USA beyond 15Dec2014.

Please suggest me the best approach to continue my stay in USA