Have you tried Vanish Oxy Action spray (from supermarkets)? I honestly am not a director of their company, nor do I own shares in the product, but the head of our domestic team at work suggested it to me when I had a similar problem involving a cream carpet showing souvenirs of various beverages including Ribena, and it was so effective that I now actually find myself telling people about it! It did need several goes on the oldest stains, but - at the risk of sounding terminally sad - it did do exactly what it said on the tin.