Find a calf, even if it is a holstein off a dairy , to graft on her so that you don't lose the lactation or have to milk her or ruin the udder.. Unless you are wanting to milk her.
I graft calves on nurse cows all the time. Preferably get one directly off a dairy, that has had colostrum, but in the event of not being able to do that and the stockyard is the only option, regardless of what they say, give it at least one bottle of colostrum - replacer- and yes it isn't cheap, and then a couple of hours later, give it at least 1 bottle of milk from your cow to get the milk processing through it's system. Or get her in a chute and put the calf on her. Cattle work by smell, and they will smell the calf's butt and if the manure doesn't smell right will be less likely to want to take it. Of course there are those that will take any calf.
Also, take and skin out the dead calf like a tube, and slide it right over the new calf so that it smells like "her calf". I can talk you through it if you have never done it. Once the calf gets on the teat and gets a good meal, separate them and then put them back together 12 hours later. Often by then the cow will welcome the relief of the udder pressure, and they can be left together. If she is not trying to butt it across the barn or into a wall, she will tolerate it and in a day or two will decide it is hers. The cow will lick the calf and often you will find the "skin" in a little pile on the ground. If not, just slide it back off after 2-3 days.
Calves die and sometimes there is nothing you can do, or should have done differently. It's part of having "livestock" ; you are going to have "deadstock" also.