Div Floating in Bootstrap 3 following Scroll

Good morning!

I have the following code:

<div class="container">
    <div class="row">
        <div class="col-md-5">
                <?php
                $hostdb = "**********";
                $userdb = "**********";
                $passdb = "**********";
                $tabledb = "**********";

                $conecta = mysql_connect($hostdb, $userdb, $passdb) or die (mysql_error());
                @mysql_select_db($tabledb, $conecta) or die ("Erro ao conectar com o banco de dados");
                mysql_set_charset('UTF8');

                $busca_query = mysql_query("SELECT * FROM imoveisvenda WHERE imoveisvenda.dormitorio = 1 UNION ALL SELECT * FROM imoveislocacao WHERE imoveislocacao.dormitorio = 1")or die(mysql_error());

                if (empty($busca_query)) {
                    echo "Nenhum registro encontrado.";
                }

                while ($dados = mysql_fetch_array($busca_query)) { ?>
                <img src="<?php echo "$dados[bancoimgthumb]";?>" class="img-responsive"> <?php
                echo "<b>Imóvel:</b> $dados[imovel]<br />"; 
                echo "<b>Localização:</b> $dados[localizacao]<br />"; ?>
                <p style="color:red"><b>Tipo: <?php echo "$dados[tipo]"; ?></b></p>
                <b>MAIS DETALHES:</b> <a href="<?php echo "$dados[file]"; ?>?id=<?php echo "$dados[id]";?>">Clique aqui!</a><br />
                <?php echo "<hr>";
            }
            ?>
        </div>
        <div class="container">
            <div class="col-md-7 banner">
                <form class="form form-inline" role="form">
                    <legend style="margin-top:1.5%;">Busca Avançada</legend> <br>
                    <div class="form-group col-md-12">
                        <label for="bairro" class="col-md-6">Cidade</label>
                        <div class="col-md-6">
                            <select id="cidade" name="cidade" class="form-control">
                                <option>Carmo de Minas</option>
                                <option>Itamonte</option>
                                <option>Itanhandu</option>
                                <option>Passa Quatro</option>
                                <option>Pouso Alto</option>
                                <option>Soledade de Minas</option>
                                <option>São Lourenço</option>
                            </select>
                        </div>
                    </div>
                    <br><br>
                    <div class="form-group col-md-12">
                        <label for="bairro" class="col-md-6">Bairro</label>
                        <div class="col-md-6">
                            <input type="text" class="form-control" id="bairro" placeholder="Bairro">
                        </div>
                    </div>
                    <br><br>
                    <div class="form-group col-md-12">
                        <label for="valor" class="col-md-6">Valor</label>
                        <div class="col-md-6">
                            <input type="text" class="form-control" id="valor" placeholder="Valor">
                        </div>
                    </div>
                    <br><br>
                    <div class="form-group col-md-12">
                        <label for="dormitorios" class="col-md-6">Dormitórios</label>
                        <div class="col-md-6">
                            <input type="checkbox" value="1" name="1"> 01 &nbsp;&nbsp;
                            <input type="checkbox" value="2" name="2"> 02 &nbsp;&nbsp;
                            <input type="checkbox" value="3" name="3"> 03 &nbsp;&nbsp;
                            <input type="checkbox" value="4" name="4"> 04 &nbsp;&nbsp;
                            <input type="checkbox" value="5" name="5"> 05
                        </div>
                    </div>
                    <br><br>
                    <div class="form-group col-md-12">
                        <label for="garagem" class="col-md-6">Garagem</label>
                        <div class="col-md-6">
                            <input type="checkbox" value="1" name="1"> 01 &nbsp;&nbsp;
                            <input type="checkbox" value="2" name="2"> 02 &nbsp;&nbsp;
                            <input type="checkbox" value="3" name="3"> 03 &nbsp;&nbsp;
                        </div>
                    </div>
                    <br><br>
                    <div class="form-group col-md-12">
                        <label for="tipo" class="col-md-6">Tipo</label>
                        <div class="col-md-6">
                            <input type="checkbox" value="residencial" name="1"> Residencial &nbsp;&nbsp;
                            <input type="checkbox" value="comercial" name="2"> Comercial &nbsp;&nbsp;
                            <input type="checkbox" value="rural" name="3"> Rural &nbsp;&nbsp;
                        </div>
                    </div>
                    <br><br>
                    <div class="form-group col-md-12">
                        <button type="submit" class="btn btn-default col-md-6 col-md-offset-6">Realizar Busca</button>
                    </div>
                    <br><br>
                </form>
            </div>
        </div>
    </div>
</div>

The div on my right side, col-md-7 banner is a div with an "Advanced Search". I would like to make her follow the scroll, because the page generates an inquiry on the bank of real estate. I want to give the user the option to do an advanced search if he wants, anywhere on the page.

I have tested several codes, unfortunately none worked the way I wanted.

Can you help me?