var dlink1 = $('a.addlink1').attr('href');
var dlink2 = $('a.addlink2').attr('href');
var dlink3 = $('a.addlink2').attr('href'); // is this correct..?
I would question why you are using classes, rather than ids, for what appear to be specific elements; particularly for 'submitbutton' - I assume there is only one.
But, as far as a little digging tells me, the get() method is not used to add parameters to a url - unless I've missed something(?). You need to append these values manually using encodeURIComponent
window.location = '/cart.php?' + encodeURIComponent(somegets);