Writing the whole project would take a while, but here's a few pointers...
Use the $_GET variable to get data from a query string. So if you had:
dbfetch.php?item=4&color=red&quantity=3
In dbfetch.php you'd have this somewhere up top:
$sql = "INSERT INTO tblWishlist VALUES( '";
if( isset($_GET['item']) && !empty($_GET['item']) )
{
$sql .= $_GET['item'] . "', '";
}
if( isset($_GET['color']) && !empty($_GET['item']) )
{
$sql .= $_GET['color'] . "', '";
}
if( isset($_GET['quantity']) && !empty($_GET['item']) )
{
$sql .= $_GET['quantity'] . "')";
}
So at the end, you'd have a SQL string to execute built.