Fireplaces, Heating Stoves, Flues and Chimneys - Repairing Stucco on Fireplace with Flagstones Help!

Hi. We have a 1929 Stucco Tudor House with the original stucco. We had vines growing up our fireplace and noticed that they were growing under the flagstones outlining our chimney, pushing them out. We took down the vines to repair the stone and small hole there was in the stucco and when we got done we were left with a stone peice, the top crumbled into the house still and not just a small hole in the stucco but a crack all the way down, and also a hole at the top, 12x8 inches. There is no lath showing at all and the inside is hollow looking down, as the stucco does not go to the fireplace masonry. It is one the side of the chimney (approx 18inches by 6 feet) so I have thought that is there was some way to repair it to make it look almost the same color / texture as the old stucco we could do it ourselves as it is a self-contained piece and cant be seen from head-on view of the front of the house. However I dont know how to get the stone that is from the front of the house where the chimney goes in, back on. Would I need to dig out the pieces and just get a new stone, are there techniques for making it stay? (its 6 feet in the air) Are there products you can buy to tint the stucco? Or is this too big of a mess to handle yourself?