how to arrange the "add cart" button?

[d.crysty23]

 I want to arrange the "add to cart" button so that it would be on the right side and the "quantity" field to be on the same line but on the left side, at the end. I've attached the respective code and an image to explain what I want.

I hope you can help me

Thanks!

.proba{display:inline;}

#quantity_wanted_p input {
	width:50px;
	border:1px solid #cdcdcd;
}