SQL & PL/SQL

I am writing a Stored Procedure where I select data from various queries, insert the results into a variable and then I insert the variables into final target table. This works fine when the queries return only one row. However I have some queries that return multiple rows and I am trying to insert them into different fields in the target table. My query is like

SELECT DESCRIPTION, SUM(AMOUNT)
INTO v_description, v_amount
FROM SOURCE_TABLE
GROUP BY DESCRIPTION;

This returns values like

Value A , 100
Value B, 200
Value C, 300

The Target Table has fields for each of the above types e.g.

VALUE_A, VALUE_B, VALUE_C

I am inserting the data from a query like

INSERT INTO TARGET_TABLE (VALUE_A, VALUE_B, VALUE_C)
VALUES (...)


How do I split out the values returned by the first query to insert into the Insert Statement? Or do I need to split the data in the statement that inserts into the variables?

Thanks
GB