[Lynne]

Two problems with your CSS. The first problem is that the right div width is set::

.postbit .userinfo .userinfo_extra, .postbit .userinfo_noavatar .userinfo_extra {
...
    width: 300px;
}

AND the left width is set to 50%:

.postbit .userinfo .contact, .postbit .userinfo_noavatar .contact {
    clear: right;
    display: block;
    float: left;
    position: relative;
    width: 50%;
}

So, change the width to something like 150px and the other width to something like 80%. See if that fixes the issue.