Personally, I'd change the food indeed. Not just in the hopes of getting her to eat more, but because (even if the price tag doesn't suggest so) that brand is serious junk food. It really is - you'd be doing just as well with a generic brand of grocery store floor sweepings.
Rather than launch into a long explanation of what's so wrong with that food - instead, here's some information on how to choose a good food. No dog food can magically be any better than the ingredients used to make it, and this page gives you an idea of what to look for, what to avoid, and why. With that information, you should be able to see for yourself what's wrong with SD and to make a reasonable assessment of any other food you look at:
www.boxerworld.com/feeding For information on what the ingredients are of over 700 different foods, plus ratings and reviews, you may find this site rather helpful:
www.dogfoodanalysis.com/dog_food_reviews
Beyond changing to a better quality food, I'd suggest putting the food down for the pup - give her 20 minutes to eat, then pick the bowl up and put it away until the next meal time. She should be offered small meals about 4 times a day at this age - and it won't hurt her to skip one, whereas it will help to teach her to eat when food is offered. You might also consider moistening the kibble with a little warm water (check that it isn't preserved with citric acid first - if it is, it shouldn't be moistened) prior to feeding. That can sometimes help with young pups who don't really recognise dry kibble as food.