So I'm trying to create a forum with avatars, but right now the text is going below the avatars and not beside them. How can I fix this?

Here is the CSS:

.postbox{
    text-align: left;
    margin: auto;
    background-color: #dbfef8;
    border: 1px solid #82FFCD;
    width: 100%;
    margin-top: 10px;
}   

.postfooter{
    width: 100%;
    border-top: 1px solid #82FFCD;
}

.postheader{
    width: 100%;
    border-bottom: 1px solid #82FFCD;
}

.posttext{
    width: 70%;
    text-align: left;
    border: 1px solid #82FFCD;
}

.postavi{   
    width: 20%;
    text-align: left;
    border: 1px solid #82FFCD;
}

and here is the html:

<div class="postbox"><div class="postheader">
                            <b><span>CyanPrime!!~::##Admin##::~</span></b>

                        </div>
                        <div class="postavi"><img src="http://prime.programming-designs.com/test_forum/images/avatars/hacker.png" alt="hacker"/></div><div class="posttext">Let's test the Hacker Avatar.</div>
                        <div class="postfooter">
                            [<a href="http://prime.programming-designs.com/test_forum/viewthread.php?thread=25">Reply</a>] 0 posts omitted.
                        </div>
                    </div>