SQL & PL/SQL :: POS CSV File With XML Format

I received a POS csv file with XML format that contain a multiple customer column and information within a csv file. I need to extract store number and associate ID from a csv column. I had already loaded the csv file to a external table and I am stuck on how to retrieve the data to a stage table along with other csv column.

For example, I need to pull data from col1, col2, col3, and col4 which col4 contain data for store_numner and associate id from a external table to a staging table which my staging table have col1, col2, col3, store_nbr column, and associate id.