As mentioned in FOOD SAFETY TIP #4: Raw Egg Yolks, egg yolks can only be stored for a few days.
The best way to store intact raw egg yolks is to immerse them in cold water in a covered container and place them in the refrigerator.
This helps by keeping air (and the carried bacteria) away from the surface of the egg yolk.
This will extend the storage time from "a few days" to "several days". That's not much but it might be all you need. Also, even if you just need to store them for a couple days, storing them in water will keep them better and safer.