I am making a full bath out of a half, how do I move the toilet away from the wall to fit the shower?

I am wondering how difficult it is to move a toilet drain as well as the sink and install a shower. I would likely remodel the entire space replacing flooring and the walls. How much would it cost to have a plumber do this kind of work. As some one who has not done a lot of pluming work is it something I should not try to do myself? I would like to do as much of the work myself as I can to lower my cost. If I can avoid any contractor help I will. Any suggestions or helpful comments would be greatly appreciated.