Does my bathroom addition require breaking the concrete?
I believe you are trying to cram to much in too little of space. The best option is to break the floor, and repair it, it will save you the "step up" you are creating with the 2X4 sleepers on the slab.

You may be able to find a plumber or perhaps DIY the cutting of the stack and tying in a line to the toilet that flushes through the wall. They are out there but it looks like your soil stack is too tight in the corner. You need to find a way to get the soil pipe out of the wall at the 15" mark. Code requires 30" for the area a toilet sets in, 15" is the center line of that space. 

Actually the info I just gave will be wrong to a degree. You will need a vent for the new toilet and it will most likely be illegal to tie it into a line that directly serves another toilet with out another branch coming off of the main to serve the new toilet.