If your download is at 1 megabit per second it'll take about 144 hours to download
As far as playing online, 1 Mb should be acceptable but it'll depend mostly on latency rather than bandwidth (i.e. how much of a delay there is when sending/receiving between you and servers)
http://www.howtogeek.com/138771/htg-explains-how-latency-can-make-even-fast-internet-connections-feel-slow/