If you are installing a SQL Server Cluster on a Windows Cluster thern you need a shared disk.

If this cannot be provided by the storage infrastructure you can use a third server to run ISCSI target software to provide the shareable disk but by doing this you have introduced a single point of failure, which makes clustering SQL Server a bit pointless.

Have you considered using SQL 2012 Always On (ie database mirroring) to achieve your HA objective. This also neds a Windows cluster, but does not need any shared disk. You may need a third Windows instance to act as a Witness for the cluster, but this can be a low-spec instance. With Always On you get the high availability you are after, plus you can use the target machine for read-only queries (you need to license the passive machine to do this).