1.for Changing Background Image serach this , and Replace your Image
Ex:
body {
background: #c2c6c7 url(http://i43.tinypic.com/2ro74o3.jpg) no-repeat center top;
2.If u want to change/Remove Title in Blogger Then Goto <div id='header-wrapper'>
and seach the code contains "title",'description' and remove them
Ex:
<div id='header-wrapper'>
<b:include name='description'/>
Note:If You remove whole code then you get <div> Problem.so be carefull while deleting "Title"