Hi Nabil,
We can perform as suggested by Robert...
As well as you can take perform one more way which seems to be bit easy too.
1. Copy the production system to the test system.
2.Take an export of your test system using SAPINST and see how much time it takes for export.
3. Create one more system and install oracle 11g and latest SBP Patches.
4.Import the test export in it.
5.Calculate the downtime required
Advantages of this method are.
1.Your DB will be re-organized. the Sizeof the DB in the target system will be reduced compared to the source system with NO loss of data.
2.You can install latest oracle version with patches.
Either you can do as i suggested or Robert whichever suites to your landscape.
Thanks and Regards,
Vimal