Cost of Joist / Structural Repair?

[Matthew Do]

Hi, first post so I hope this is the correct forum. 

Situation: Typcial two-story Philadelphia row home. Second story beam at the stair is sagging / deflecting. Was previously supported years ago with lolly columns at both the front and back of the stair... Front: one between first story floor and first story ceiling, another lolly directly beneath that, and cement footing w rebar in the basement slab beneath everything. Same thing at the back of the stair... 1st floor lolly, basement lolly, and footing. A new header beam was also installed underneath the stairs in the basement (the basement lollies push up against this). 

Problem: Joists are making impressions in the first floor ceiling and at a couple points in the walls upstairs and downstairs. Also a couple cracks in a the walls. Second story floors are very noisy and mushy in spots. Definitely some shifting happening, but slowly. My guess is that the two lollies were not leveled properly, and the weight of the 2nd floor shifted, causing increased pressure on other joists and a new set of problems over time. 

I plan to have a structural engineer inspect and make a plan. Assuming I'll have to open up the 1st floor ceiling and pay to have several joists sistered. Also assume the lollies will need to be replaced or maybe just re-leveled. And would somehow like to stiffen up the upstairs floor so it feels level and firm. 

Question: Wondering what this will cost in total to set right. I've looked for pricing info related to this kind of thing and it's very hard to find, so I'm praying someone out there who has done this sort of thing can give me a realistic ballpark of what this would cost. 

Thank you!