First, sign into your Blogger Dashboard, click LAYOUT, then click the EDIT HTML sub-tab. This will open the template editor window. Add this block of codes into your template just above the </head> tab which should be very near the top of the template:
<meta http-equiv="refresh" content="0;url=http://newurl.com"/>
It should Look Like This
<head>
<meta http-equiv="refresh" content="0;url=http://newurl.com"/>
</head>
Replace http://newurl.com with the domain you want to redirect to the olb blog.
That's it! Now, all your old blog traffic will be redirected to your new address.
If you have any questions,ask here.