Go to Dashboard> Appearance> Editor > [on the right column menu] Style.php > scroll down the code until you see this:
}
#feature h2 {
padding:0px;
margin:0px 0px 10px 0px;
color: #;
font-family: , Arial, Helvetica;
font-size: px;
}
I did not try this myself, but I would bet that if you changed that h2 to h1 you will have the change you are looking for. > then click "Update File" > check the blog to see if the change happened. You can always go back and change if back to h2 if that was not the one.