transfer from terminal 3 to terminal 2 in Beijing airport

I will arrive with El Al to terminal 3 at 13:30 21/11/13
my flight to Shanghai is at 16:00 from terminal 2

do I have enough time for the transit-I will have hand baggage only -
How long does it take to travel between the 2 terminals -is it by train ? by bus?

Thanks
Gideon