Updating PHP4 to PDO - php

Question

I'm currently managing a little database for a club and I'm starting to feel more and more pressure to update the thing to PHP5. The only thing is that I'm not quite a 100% sure on how to convert this structure without messing up the whole thing. (Or starting from scratch)
Could you guys tell me if this is easily editable/updatable or if I should redo everything? (The total file is 800 lines, so I hope to not have to redo it :P)
So I open the databse with:
//Database connection settings
$mysql_server = "localhost";
$mysql_user = "user";
$mysql_password = "pass";
$mysql_database = "database";
//Connect using settings
$connection = mysql_connect("$mysql_server","$mysql_user","$mysql_password")
or die ("Unable to connect to MySQL server.");
$db = mysql_select_db("$mysql_database")
or die ("Unable to select requested database.");
Then I can create users with:
if($changeme ==1) //if user pressed save, then update table
{
$name = mysql_real_escape_string($_POST["name"]);
mysql_query("INSERT INTO Members (name,) VALUES
('$name')") or die(mysql_error());
//show end text
echo "Edit complete!<br />
<form><input type='button' onClick=\"parent.location='users.php'\" value='OK'></form>";
}else{//user didn't press save
?>
<!--Edit form-->
<form action="users.php?new=1&changeme=yes" method="post">
Naam:<br>
<input name="name" type="text" value="" size="79"><br>
<input type="submit" name="Submit" value="Create">
<input type='button' onClick="parent.location='users.php'" value='Back to list'>
</form>
}
I left out everything but name to make it shorter, it has like 30 fields.
Next we can also edit the profiles like this:
if($changeme ==1) //if user pressed save, then update table
{
$id = $_POST['id']; //get ID from form
$name = $_POST["name"];
mysql_query("UPDATE Members SET name='$name' WHERE id='$id'") or die(mysql_error());
//show end text
echo "Edit complete!<br />
<form><input type='button' onClick=\"parent.location='users.php'\" value='OK'></form>";
}else{//user didn't press save
$id = $_GET['edit'];
$sql = "SELECT * FROM Members WHERE id='$id'";
$self = mysql_query($sql);
while ($row = mysql_fetch_array($self)) {
$name = $row["name"];
}
?>
<!--Edit form-->
<form action="users.php?edit=<?php echo $id ?>&changeme=yes" method=post>
<input type="hidden" name="id" value="<?php echo $id ?>">
Name:<br>
<input name="name" type="text" value="<?php echo $name ?>" size="79"><br>
<input type="submit" name="Submit" value="Change">
<input type='button' onClick="parent.location='users.php'" value='Back to list'>
</form>
<?php
}//didn't press save