My advisor asked me to publish in an SCI-indexed journal with better impact factor (say more than 1). I found a journal with impact factor as 1.2. But the journal says that its present impact factor is based on 2015 journal citation report (JCR). It does not mention anything the year 2016. I couldn't find their name listed in 2016 report too. But I found a journal with impact factor .4 in 2016 report. My questions are

1. Is the Impact factor valid only for a year?
2. If I publish my work in a journal that says having an impact factor (in the year 2015), can I claim it when I publish in 2017?