how to create run-time variable

Hi,
I've used Data Assist to create a search.php and result.php page similar to the tutorial.
The searching works fine, but I have one small problem.

One of the search fields is a field called "funder". It is a dropdown that shows the Funder's Name as text, but searches on the ID field, "funder_id".

On the results page, I want to show the funder, but all i can show is the funder's ID -- example, Funder:3. What I want to show is: Funder: Federal Government -- the label/name field.

So I create another recorset from the table of Funders and filter it with the results of the main 'results' recordset:

SELECT *
FROM tbl_funder
WHERE funder_ID = colname

Name: colname
Type: Integer
Default Value: -1
Run-Time Value: $row_rs_products['Funding_Source']

This value doesn't work for some reason. Assuming that I have the field names right, what else could be wrong? This does not return the "Funding_Source" for each result record.
I'm guessing I don't know how to properly define the "Run-Time Value" properly?

thanks for any help.