Hello,

About getting the node where the instance is running, you can use the following query:

select Nodename from sys.dm_os_cluster_nodes

or this other one:

select Nodename from ::fn_virtualservernodes()

The query above would give you the names of the nodes on that cluster, and it will list first the active node for that instance... just add a TOP 1 and your are golden without having to access the registry.