H1B Visa Restamping

My last day of work with the company in the USA was Jan 18th 2016. I am currently in india working for a company who sponsored my B1/B2 visa in September for 10 years. On interviewing with the consulate I received a Cancelled without prejudice stamp on the H1B visa on my passport. I have 21 months remaining on my H1B visa(of total 6 years).I also have an approved I-140 PERM from the last employer in USA for green card. I have the receipt number too.I had family issues and to resolve them I came to my home country. They have now been taken care of hence I would like to go back to USA.

Q: If I get a job with an employer in USA and they decide to apply for an H1B visa, would I be subject to the lottery system again?
Q: Will the start date of the new H1B visa be from Oct 2017? or immediately from the approval date?
Q: How can I use the remaining 21 months on my H1B visa?