Importing .sql file on windows to postgresql

You should use psql command line tool:

psql -h hostname -p port_number -U username -f your_file.sql databasename 

click on the SQL Shell and log into the database and use import

Server [localhost]:
Database [postgres]:
Port [5432]:
Username [postgres]:
Password for user postgres:
psql (9.2.4)
WARNING: Console code page (437) differs from Windows code page (1252)
         8-bit characters might not work correctly. See psql reference
         page "Notes for Windows users" for details.
Type "help" for help.

postgres=# \i c:/data/data01.sql

start you psql command tool, it will give you dialog like the following

Server [localhost]:
Database [postgres]:
Port [5432]:yourport
Username [postgres]:
Password for user postgres:**********

then connect to your database

postgres=# \c yourdatabase;

then import the file

yourdatabase=# \i c:/path/path/data/data01.sql

note the / for directory separator & no spaces in file path