the main problem was that the form method was set to use get, i changed that to use post.
for the quantity to pass, i edited the quantity element to use the ID in the name:
<input name="ATCQty<?php echo $row_rsProducts['id']; ?>" type="text" value="<?php echo $row_rsProducts['prodMin']; ?>" size="2" />
then edited the binding for the quantity in the add to cart code from:
$eCartMGP_itemQuantity = floatval("1");
$eCartMGP_itemQuantity = "".$_POST["ATCQty".$row_rsAddSelected['id']] ."";