EXPORT specific columns to INSERT statements
Use Import/Export wizard and instead of exporting the entire table, choose sql to export specific rows and columns.

You can write sql like : select column1, column2 from Table1 where some_condition or if you don't care about specific data then you can use top command to extract any number of rows that you require.

Edit : Below are screenshots for Import export Wizard (Launch it from SSMS):







EDIT:  

@Robin IN your situation, you can do 2 things - 


Go for something like Redgate's sql data generator that will generate test data -- OR --
You can do a 1 time import of data as I suggested and then backup database and for your rest of testing you can just keep restoring the database from the backup (keeping in mind the data that you imported will not change). I cant think another way of doing what you want to achieve, so will keep this for others to answer ...