Normalising an existing table - how?

Hi all,

I have an existing table containing a column in it containing a money 
value. I would like to normalise this column into a separate table, as 
the money value is to be expanded to contain a tax value, etc.

I have been trying to find a SQL query that will do the following:

- Select the money column from the table
- Populate the new normalised table with each row containing the value 
from the original money column
- Write the primary keys of the new rows in the normalised table, back 
to a new column in the original table added for this purpose.

This third step I am struggling with - can anyone suggest a query that 
might achieve the writing back of the primary key to the original table?

Regards,
Graham
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