Use FTP/SFTP to upload your dump file. You can just temporarily put it in your home directory.
In your command the < is a redirect character, in this case taking the contents of the file dump.sql and using it as input for the mysql command before it. In this case, it's assumned that dump.sql is in the same directory that we are executing the command from, but it also could include a path such as...
mysql --host=mysql.mydomain.org--user=MyUsername --password=MyPass DatabaseName < .path/to/dump.sql
AND if your file is named websiteBackup140306.sql or something like that, then just chance dump.sql to websiteBackup140306.sql