Coding in HTML

 <div id="site-content">
                <div class="site-content">
                    <div id="site-content-left">
                    <h1>NEW COURSE OFFERINGS</h1>
                    <div id="site-content-dproc">
                        <div id="slider">
                            <div class="slide-img">img</div>
                            <div class="slide-text">
                                Consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat.Consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat.
                            </div>
                            <div class="clear"></div>
                            <div class="slide-read-more">
                                <a href="/arm/dprocashinutyun">Read More...</a>
                            </div>
                        </div>
                    </div>
                    </div>
                <div id="site-content-right">
                    <div id="embeddedExample" style="">
                        <div id="embeddedCalendar" style="margin-left: auto; margin-right: auto">
                        </div>
                    </div>
                </div>
                <div id="site-content-ushadrutyun">
                <?php
                while($result_ushadrutyun_main_arm = mysql_fetch_array($query_main_ushadrutyun_arm)){
                    print $result_ushadrutyun_main_arm['short_content'];
                }
                ?>
                </div>
                </div>
                <div class="clear"></div>
                big gap
                </div>
            </div>

Styling with CSS

#site-content{
    background:red;
    margin-left:250px;
}
.site-content {
width:740px;
margin:0 auto;
padding:25px 0 0 0;
}
#site-content-left{float:left;background:orange;}
#site-content-right{margin:5px 0 5px 10px;float:left;background:blue;}
#site-content-left h1{margin:0;font-family:erevan;font-size:25px;color:#0463a7;}
#site-content-dproc {background:url('../images/site-dproc.png');width:490px;height:370px;padding:10px;}
#site-content-dproc:hover{background:url('../images/site-dproc-hover.png');}
#site-content-news{float:left;}
#site-content-social{float:left;}
#site-content-news  .site-news-grey {background:url('../images/site-news-background.png') no-repeat;width:270px;height:182px;float:left;padding:25px;margin:0 10px 10px 0;display: inline-block}
#site-content-social #social-twitter{background:url('../images/social-twitter.png') no-repeat;width:70px;height:70px;margin-bottom:5px;display:block;}
#site-content-social #social-youtube{background:url('../images/social-youtube.png') no-repeat;width:70px;height:69px;margin-bottom:5px;display:block;}
#site-content-social #social-facebook{background:url('../images/social-facebook.png') no-repeat;width:70px;height:72px;margin-bottom:5px;display:block;}
#site-content-social #social-google{background:url('../images/social-google.png') no-repeat;width:70px;height:70px;margin-bottom:5px;display:block;}
#site-content-social #social-dasaran{background:url('../images/social-dasaran.png') no-repeat;width:70px;height:262px;margin-bottom:5px;display:block;}
#site-content-grey-news{width:670px;}
#site-content-ushadrutyun{
    background:url('../images/content-ushadrutyun.png') no-repeat;
    width:198px;
    height:123px;
    padding:10px;
    word-wrap: break-word;
    font-weight:bold;
    text-align: center;
    font-family:erevan;
    overflow:hidden;
    color:#0463a7;
    margin:15px 0 0 0;
}



#site-content-ushadrutyun p {margin:0;}
#aaa {background:url('../images/news-calq.png') no-repeat;width:139px;height:78px;position:relative;top:-50px;}
#site-content-news h1 {margin:15px 0;font-family:erevan;font-size:25px;color:#0463a7;text-align:center;}
#corner-calq a {
    text-decoration:none;
    font-family:erevan;
    color:#0463a7;
}
#corner-calq div {
    -moz-transform: rotate(-30deg); 
    -ms-transform: rotate(-30deg); 
    -webkit-transform: rotate(-30deg);
    -o-transform: rotate(-30deg); 
    transform: rotate(-30deg);
    }
#corner-calq a:hover {text-decoration:underline;}


.slide-img {float:left;margin-right:10px;}
.slide-text {text-align:justify;font-size:15px;}
.slide-text {height:250px;word-wrap:break-word;}
.slide-read-more {float:right;}
.slide-read-more  a{    margin:80px 0 0 30px;-moz-transform: rotate(-30deg); 
    -ms-transform: rotate(-30deg); 
    -webkit-transform: rotate(-35deg);
    -o-transform: rotate(-30deg); 
    transform: rotate(-30deg);}

Is there a solution for the big gap after the content with a size of approximately 300px?