How to extract only integers from string and chosen letters?

I am successfully extracting integers from string.

How to do it but including strings: "k ", "m " and "b "?

This code takes given website code and extracts numbers, I need numbers and "k ", "m " and "b "

$objectId = 15259;
$lines = file('http://testwebsite.com?obj=' . $objectId);
foreach ($lines as $line_num => $line) {
    $lineCrawl = htmlspecialchars($line);
    $stringSum = "$stringSum$lineCrawl";
}

function get_string_between($string, $start, $end){
    $string = " ".$string;
    $ini = strpos($string,$start);
    if ($ini == 0) return "";
    $ini += strlen($start);
    $len = strpos($string,$end,$ini) - $ini;
    return substr($string,$ini,$len);
}

$parsed = get_string_between($stringSum, "Current guide price", "Today");

$guideprice = ereg_replace("[^0-9]", "", $parsed); 

echo $guideprice; 

Change 0-9 to 0-9kmb should work