F1 OPT to F1 --> Stamping is required ?

[SiriP]

Hi I ame to US on F1 visa in Jan 2011. I completed my masters and current I am on OPT Extension and its valid until October 2014. My H1B application not picked from lottery yet. I have to travel to india this year for sister marriage. Here are my questions:

 

1. Can I travel to India before Oct 2014 (July & Aug) on the OPT Extn status ?

2. Can I need F1 visa stamp again if I transfer again to F1 from OPT Extn (I have valid visa stamping until 2015 Dec)