basement blues

We live in a semi detached row home. Our dining room started take on a lean on the wall that seperates the 2 houses. after taking down some paneling in my basement I was able to determine what the problem was and how to correct it. I purchased a couple of steel post< from home depot. after getting home and setting things up i noticed that the post holding the load bearing support was actually position in my neighbors basement. i figured not a problem I could just let her know what needed done and do it. My gf pointed out to me that if I go into the neighbors basement and do anything and it causes serious problems I could be at fault. i then noticed that do to water coming into the front of the house it has torn the hell out of the front window,window frame and the actual stone foundation. i desperatley need some help.