the bacteria is living in your live rock, on the walls, on the substrate, anywhere it can attach...but there should be plenty on your live rock as long as you don't immediately add a bunch of new fish when you transfer them to the new tank...
if it were me, i would get the new tank, get the live rock you will want, and let it cycle and then move the other rock/inverts/etc
if it were me, i would get the new tank, get the live rock you will want, and let it cycle and then move the other rock/inverts/etc