Either user can upload a spreadsheet for that or I shall provide a template file to fill up the data. When I checked there is no provision for uploading a
speadsheet in my galaxy instance.  

Two simple options:

(1) have users convert their spreadsheet data to csv/tabular format; Galaxy works well with tabular data.

(2) create your own datatype:

http://wiki.g2.bx.psu.edu/Admin/Datatypes/Adding%20Datatypes

There are many examples for tabular data such as SAM, BED, GFF, etc., in the Galaxy base—see tabular.py and interval.py

Best,
J.