I'm in DC. *Everything* is expensive.

It's a bit of an eyesore but falls into the DIY-or-not-at-all bucket for me.
I was thinking that a series of thin joint compound applications, feathering further and further, might hide it. But it sounds like you think that's not a good approach. I could try to sand it down, although if it *is* the stud, that won't work.
I am not an expert, but am a diy'er that has successfully fixed problems like this. If you have time, you can do it yourself.
First thing to do, go to the big box store and get you a five gallon bucket of compound and a 12 in drywall knife. If budget permits, get a few smaller knives as well. I, know, you won't need five gallons, but its not much more expensive that an small bucket, and you will need more than a small bucket.
If you have never mudded before, just do one side of the hump at a time. Put the compound on the wall to the left of the hump, the width of you knife. Place one edge of the knife on the hump and drag the mud down to get your first application. Get is as smooth as possible without divots, but dont worry about small imperfections.
Let that dry, do the other side of the hump.
After that side dries, feather out a wider coat.
You should end up with an area on each side of the hump that feathers out about 18".
I don't care what your budget is , but that room looks like it was just redone and its sanding time, which is a mess.
Get one of these:
http://www.homedepot.com/p/Hyde-Dust-Free-Drywall-Hand-Sander-Kit-with-6-Foot-Hose-09165/100659771
To get a nice smooth finish, do what they do to sand down body filler on cars. Block Sand. Sand one way at a 45 degree angle, then the opposite way at a 45 degree angle. In other words, sand in an x pattern. You will never have an uneven sanding job.
May need to do a few touch ups, prime paint the whole wall, and call it done.
Don't know if the pros would agree with the above method but it has worked for me on walls and ceilings. The patch has held with no cracks.