ok, well first, where is the list of products coming from? that is a good place to start.
with the html code for the form, you should use html array syntax like this:
<input type="radio" name="product[]" value="product_name"/><input type="text" name="qty['product_name']"/>
then look at the values in the $_POST array when the form is submitted. that should be enough to get you started.