My Current Status - Greencard since June' 2010

I have visited India from October' 17 2010 - February' 4 2011 (Total 111 days)

Now, I need to go back to India again for around 3 months (Approx May'10 2011 - Aug'10 2011) which will be around 93 days.

I need your expert advise for the following questions:

1. When you count from October 17' 2010 (First Trip departure date) to October 16' 2011, I will be more than 180 days out of the country. So is this correct based on the USCIS guidelines ?
2. But in each calender year I will not be out of country for greater than 180 days. So, as a GC holder can I make the above visits without resetting my 'Continuity of 5 Year of Residence' clock ?
3. Basing on responses for 1 and 2 above, do I need to file for Re entry permit?