Do you have a basement or somewhere the wires come into the house?
If you know nothing about electrical, get an electrician or someone else you know who is knowledgeable about a fuse box.
You need to shut off the power around the box, then remove the plaster yourself. The box will be screwed to the studs(hopefully) and you will only need to remove the front cover. Then put a piece of sheetrock around the panel and turn the power back on.
It is not hard to do, just not safe if you do not know what to do.
It will take someone with experience about 30 minutes to complete this part of the job. Just continue on with other demo and figuring out what will be next besides this.
I see wire lath in the corner, having fun yet?
This stuff is nasty, wear good gloves.
Just start asking around your neighbors or Friends.