[Ron6519]

It really helps to do the research before the tools are picked up, but this is a pretty easy fix.
Put the stud where ever you want. Placement is irrelevant if the door trim is wider then brick molding. . The gap on the exterior can be taken up with trim. If you're using brick molding, put a 3/4" 1x4 on each side and the trim will cover the gap.
Ron

 

[Willie T]

One fix might be to jump down to the local door salvage yard (most areas have one or two) and pick up a 34" door. If it is not good enough, at least it will work till a special ordered one arrives. Changing out that door later will take about a half hour at most.