Add applications (Ganglia, Impala, Hunk) to running EMR Cluster

I created an EMR cluster but I forgot to add some applications that I'd like to play around with. It's a "long running" cluster so I cannot just create a new one.

How can I add Ganglia, Impala, and Hunk to a running cluster?

Also, is there anything else that needs to be done to have HBase report metrics to Ganglia?