H1b Stamping ( I have current H1 valid till sep 2013 )


I have below questions regardig my H1B Visa Stampin

1. My current H1B Petition is valid till Sep 30 2013 and i applied for H1B extension and got approved for 3 years till sep 30 2016) I am planning to go to India in July. 

2.If i wanted to goto  India in July, On which H1 should i  go for stamping intial H1 or Extension .

3) IS there any specific time that   we can  attend Visa interview for the extension?

Appreciate your response. Please let me know.