Are you in Chicago?

I only ask because this is a *thing* here and I just saw a local thread on it. The consensus is that flipping the stairs from the kitchen to dining room is about $10-12k, if you do it to code (almost certainly required if you want it to be marketable) Likely, the existing stairs are very far off from current code and when you make any alterations to them, you need to follow current code.

Once you do the stairs, doing the dormer is a whole project as well. We have a required ratio of floor square footage to ceiling height needing to be 7'. Framing and finishing the space isn't necessarily the expensive part, but adding HVAC, windows, electric, etc... can add to it.

All in, flipping our stairs, adding a back half dormer with 3/4 bathroom and finishing the other side of the attic was going to be $100k. We got the kids bunk beds. :D

Yikes! Thanks for the info.