How to add Comment button widget

1.Now login to your Blogger Dashboard and navigate to Layout --

Edit Html and check the check box which says

“Expand widget templates”

2.Find this piece of code(ctrl+f)

<div class='post-header-line-1'/>

3.copy and paste this code after 1st code

<b:if cond='data:post.allowComments'>
<a class='comment-bubble' expr:href='data:post.addCommentUrl' expr:onclick='data:post.addCommentOnclick'><data:post.numComments/></a>
</b:if>

4.Then Find this code(ctrl+f)

</head>

5.Paste This Code after that code

<style type="text/css">
.comment-bubble {
float: right;

background: url(http://i49.tinypic.com/2vugahu.jpg) no-repeat;
width: 55px;
height: 38px;

font-size: 18px;
margin-top: -15px;
margin-right: 2px;
text-align: center;
}
</style>

p/s... you can change buble comment url..