Using Oracle Datapump when target table has additional column
Just import your data into a a staging table at the target database. Then write a SQL staement to copy the rows from the staging table into the target table while giving the two new columns an explicit value. 
So something like this; 

The following syntax should work on 11g

impdp user/password directory=import_directory dumpfile=data.dmp  REMAP_TABLE=schema.source_table_name:staging_table_name


Then, simply do something like this;

INSERT INTO target_table (column1, column2, column3, column4, column5)
SELECT column1, column2, column3, 'New Data', 'New Data2'
FROM staging_table_name 


After which you can drop the staging table.