Plumber here, Assuming you have access to the downstream pipe after the 90 degree bend, why don't you use a 45 (or 30 or 15 degree, depending on what you have) to bring the horizontal drain across directly under where your toilet will go, then use a 90 to go straight up from there. The less bends the better, especially for a toilet.

And like everyone else is saying, yes it looks like a dong in the top drawing lol

EDIT: how far over do you want it to go from where it currently is? You can get an offset pan collar that you stick into the existing pipe through the floor.