Hai,
Are the following steps correct:

1) Stop the complete application tier.
2) Stop the Database.
3) Move Databasefiles, Controlfiles, Redologs & Archivelogs to the newly
created respective Cluster Filesystems from Local Filessystem.
3) Modify init.ora file for control_files, log_archive_dest_n entries
and re-create the spfile.
4) Startup Database Mount.
5) Rename Redologs & Datafiles with new names.
6) Open the Database.
7) Shutdown the Database again.
8) Install the Oracle Clusterware on existing Database Node.
9) Start the Oracle Clusterware.
10) Modify the spfile and add Cluster Database parameters.
11) Register the database in the OCR Registry.
12) Now, prepare the second node of the two node RAC.
13) Install Oracle Clusterware & Oracle RAC binaries on the second node.
14) Join this to the existing single instance RAC Database.
15) Do a final test by shutting down and starting the services etc.

regards,
Dileep Tallam