Extending building's free wifi to my mom's apt where there is no signal?

Kidsandliz went on a bit of a rant said
2

My mom lives in a building that provides free wifi to each floor’s lobby. The signal vanishes about half way down the hall to her apt. Those who live close enough have free wifi in their apt, those who live near the end of the hall do not. Mgt has no intention of doing anything to extend it.

Anyone have any ideas for a temporary solution I can bring with me each time to get a signal in her apt? I have no access to any ethernet cables, there are two power outlets in the lobby (this is a retirement community so likely I could put something behind the end table and no one would notice or steal it). Or is there something I could put in her apt that would pick up the signal?

Signal loss happens generally anywhere from 8-15 paces from her apt (sometimes you can get closer - just checking what my computer gets walk walking down the hall - the one and only time I got a signal at her apt door it was lost the minute I went through the door), hall walls and walls between the apartments are plasterboard over cement with steel girders when needed. The elevators are on her side of the lobby and her apt is on the elevator side of the hall. Lobby ends at the hall so no option of putting anything anywhere that isn’t going to have the elevators in the line of sight.

Any suggestions appreciated. I’d love to sit in her living room and use the internet. Or better yet lie in bed at night and do so (bedroom is at the far end of the apt - she has the last apt on the hall).