I am no SAP expert, i beleive it all depends on what way you wish to make SAP part of your career. Generally speaking SAP is used in Large Organisations as an all in one package. SAP comes with many modules which are useful in running various departments of a large organisation. They all make use of a central database.
If you wish to be an ABAP programmer (SAP's frontend development tool) then i guess its enough if you learn ABAP programming and know your way around SAP.
However, if you wish to accomplish more, then some functional expertise is required according to the module you want to master. Look here for some SAP training (expensive):
*www.sap.com/asia/education/schedule/schedule_IN.htm