Adding a class with a width of 90% to your input element and adding the following input-icon class to your span would achieve what you want I think.
.input { width: 90%; }
.input-icon {
display: inline-block;
height: 22px;
width: 22px;
line-height: 22px;
text-align: center;
color: #000;
font-size: 12px;
font-weight: bold;
margin-left: 4px;
}
EDIT Per dan's suggestion, it would not be wise to use .input as the class name, some more specific would be advised. I was simply using .input as a generic placeholder for your css