Dear Shivani,
SAP is a tool for performing tasks. I would suggest first complete your master degree, have some practical knowledge on HR activities (on ground basis). Once you will go thru the basic & core HR activities this will lead your carrier with more pace.
Bcoz SAP will help you to accomplish your (HR) job in a systematic way (being software/s advantage) which prohibit doubling of work at various places. But you can take the advantage only in a company which is using SAP module/s.
SAP in a very big working tool which is specially designed to smoothen & align the various "Reporting System" (Finance, HR, Production, Marketing etc.).
Having practical knowledge will help you to built your carrier in any company. Since presently there are various software, payroll packages are, so companies are working on them. Basic knowledge is a "MUST" for all.
Hope you will like the suggestion. I would like your feedback as well in coming period.