In fact, it is easy to increase order in an open system. To take a trivial example: Insert a seed in a sterile medium. Let the sun shine. A plant will grow.
Perhaps more to the point, the problem of the initial code: I agree that it is very unlikely that the first self-replicating cells had DNA, or at any rate used DNA in anything like the current system, where base pairs are read by other complex chemical structures and code for amino acid chains. Too complex to self-assemble randomly, as all you creationists would agree. But in an already existing line of self-replicating creatures (which would quickly dominate the Earth, there being no competition), there is no difficulty in evolving new structures and functions. Indded, it would be impossible for this not to happen, as more successful creatures with useful innovations would of course be those which left more offspring.
A completely false assumption.