How Much to replace floors+ beams

I am considering buying a brick townhouse which has sagging floors on the top 2 floors of a 4 family. Yes they are near the bathroom + kitchen. We were told that a 9 foot portion of the load bearing wall has been removed on the parlor floor which could have added to this sagging.
Also, in the basement there were arches underneath the load bearing wall which were removed and replaced with steel beam and steel columns.

I have read through the other posts on this issue which were very informative but I am now wondering what the cost might be for the worst case scenario? Replacing the floors and beams on 2 possibly 3 floors? And could one live in the garden apt. while this was happening?
New to all this so thanks!

By casabella |