Show total Donations

Hi I have created a site for a friend that was injured in Afganistan http://www.a-soldiers-journey.co.uk He is doing things for Charity and I have created a donations form, I am new to wordpress and was wondering if someone can show me how to add a running total of all donations that updates dynamically each time someone donates money through paypal Thank you in advance Alistair

Thanks for the reply Chris it is working to a point but the ammount isnt just showing as GBP0.00

My Short code is :

<span style="font-size:16px; color:#069; font-weight:bold;">Amount Raised</span>
<span style=" font-size:14px; color:#999; font-weight:bold;">[donations form=2]</span>

and my functions.php file I have added at the bottom:

// http://pastebin.com/kHpaHQvi originally
// http://www.gravityhelp.com/forums/topic/show-total-donations
// usage: [donations form=2] where 37 is the form ID
add_shortcode('donations', 'total_donations');
function total_donations($atts) {
        $form_id = $atts['form'];
        // function to pull all the entries for one form
        $donations = RGFormsModel::get_leads($form_id);
        // start the total at zero
        $total = 0;
        // initialize a counter for the number of donations made
        $i = 0;
        // loop through all the returned results
        foreach ($donations as $amount) {
                // add each donation amount to the total
                // change 3 here to the field ID which holds the donation amount
                $total += $amount[5];
                // increment the counter so we know how many donations there are as well
                $i++;
        }
        // change this to your locale, or, if your locale is already defined, you can remove this line
        setlocale(LC_MONETARY, 'en_GB');
        // do some formatting and return the html output from the shortcode
        $output = "We have raised " . money_format( '%i', $total) . " from $i donors.";
        // just the string above will be returned.  You can style it here or where you are using the shortcode
        return $output;
}
// needed for the above to process the donation shortcode in sidebar widget
add_filter('widget_text', 'do_shortcode');

What have I done wrong thanks Alistair