Where can I find a replacement 'head' for my Alpina VIP 42 petrol strimmer?

Where can I find a replacement 'head' for my Alpina VIP 42 petrol strimmer? The whole head assembly has cracked as it is 'cast' not steel/aluminium. I need to replace it from where it joins the shaft. Can this be done? Is there a universal 'shaft down' head assembly available anywhere?