Davey's advice is spot on, but if you don't believe him, you could always do what you should have done, and have a look at the documentation. You'll find Chapter "8 Adding Nodes and Instances and Deleting Instances in Real Application Clusters" of the "Oracle9i Real Application Clusters Administration Release 2 (9.2) Part Number A96596-01" book most illuminating.
And to echo Davey, I truly hope you are not using a mixture of versions to access the same database.
I have 15 databases running three instances of 188.8.131.52, and 3 databases running three instances of 184.108.40.206. Also I have 220.127.116.11 single instance databases distributed on the three nodes.
I have read that a node can be added or remove without shutting down the cluster, I am trying to look for some advice from people who have actually done it. Our sys admin said that 'we cannot add or remove a node from the cluster without shutting it down because we are using RAW devices.' Your inputs is appreciated.