Frozen milk

This might be a stupid question(s)... I have so much frozen milk that my baby's not a huge fan of. I want to use it and mix it with cows milk but I don't know how to. I've read that the milk is good for 24 hours after it thaws but when I thawed it in the fridge some was thawed and some wasn't. I usually just warm it until the icicles are gone so it's still cold but if I warm it will I still be able to mix it with cows milk? And then is it only good for 1 hour even if it's cold?