Zbrush UV Master Running Out Of Memory

So I am ALMOST ready to color print out my sculpture but I am officially stuck on this next step. I have poly painted the sculpture and merged all the sub tools into one tool, ran the dynamesh thing which reduced the poly count significantly while still preserving most of the poly paint information. Now I am left with a 2.5 million poly model that has poly paint info on it but no UVs and I want to get the poly paint info onto a texture.
When I try to use the UV Master it crashes every time because it runs out of memory, when I use decimation master I loose the poly paint information and it can't really be projected back on to the mesh later without peppering it with white spots that are really painful to fix... Ideally I want to UV unwrap the model, bake poly paint to texture and then run the decimation master, but it just can't be done... does anyone have an Idea how to get around this problem?

Thanks in advance!!