you would need to create a second lookup recordset to lookup the information for the selected size:
rsSizeLookup
SELECT *
FROM shopshoes
WHERE shoe_product_ref = colname AND shoe_sizes_and_colours.shoe_size = paramSize
ORDER BY shoe_size ASC
name: colname
type:text
default value: -1
runtime value: $_GET['shoe_product_ref']
name: paramSize
type:text
default value: -1
runtime value: $_POST['eCart1_1_Size_Add']
then in the add to cart button, bind the columns that need to get the selected size info to the columns from the new rsSizeLookup recordset.