Having valid H1B visa going back to work for same employer after 1 year stay in India


I was on H1B visa with valid visa tamped till September 2013 for a american construction company based in Miami.Due to some reason i came back to India in April 2013,during this time my company file my H1B extension petition which i got approved .On September 2014 i got my extension visa stamp on my passport with validity till August 2016.My ex employer is willing to rehire me for the same job .They didnt revoke my H1B and now then want me back .What did i need to do or what document i need to carry to get back to US .

they will be sending my new hiring letter soon

Please advice me