Hi Arpitam ,
You can use
GUI_UPLOAD is for getting the data from flat file(notepad,excel sheet,etc..)to internal table
GUI_DOWNLOAD is for sending the data from internal table to flat file.
After fetching data into internal table, you can easily transfer data into R/3 data base .
Link below will be helpful for you .
Import MS-Excel file directly into SAP Table - Code Gallery - SCN Wiki
With Regards ,
Juneed Manha