I am guessing $20-$25k also, but depends on the finishes and their quality(good carpet v cheap, hard wood trim v paintable, etc).
A note on the pole: I have one in my basement. It originally split the entire space in two. I wanted to regain the area it occupied, so I moved it.
Every steel beam has a marking on it's web that will state what size beam it is. The marking will look something like W8x13(that is what mine is). You can use this to find how far such a beam can span given an assumed weight load. Use a Load & Resistance Factor Design book for this(May be able to google the appropriate charts, if not, I have the book and can fill you in on what the chart says, given you know your beam size).
I moved mine over after building a second beam in my new closet wall. That way the steel pole remains, the beam span is not exceeded, and I now have a much more wide open room.
Also, to reinforce what others have said; rough framing is so easy a drunk monkey could do it given he had a skill saw, nail gun, and ram set. I would give it a whirl. They call it "rough" carpentry for a reason...it doesn't have to be exactly perfect.
If you hire out the drywall mud/tape, hire out hanging it too. Some small things that can be done while hanging the drywall will make the mud job much faster(cheaper) and will hide joints better all said and done.
As for the ceiling, in the area you are not going to use as a bedroom, maybe consider painting the exposed joist a dark color. Look around a lot of new restaurants and bars have this. It kind of hides the ceiling from your eyes. Much cheaper than any other finish option, and if you run wire, duct, conduit, or anything else in the future, you simply paint it and it blends in.