I do agree that you should not be milking her until she calves. I dont want to repeat what has already been said, but it is very normal to see blood in the milk after calving and before. this will go away after she calves after a few milkings. As far as killing the calf, all you will need to do is possibly give her milk replacer or vitamins to replace the nutrients that the calf will not be getting from the milk. Keep an eye on the calf. She should be fine. I am very confident that your cow will be just fine. I have been around many calving cows and milked them for close to 5 years. I am no expert by any means, but I dont think you have a problem here. If it does turn out that after she calves she has mastitis, (hot mastitis or (forgetting the term for the cottage cheese kind)) Just treat her with today or other treatment)) Make sure you read because usuall you do not want to give the calf the treated milk. As far as the swelling, you could rub bag balm on her quarters, that seems to work great for me!
Keep me updated!