Hello everyone,  I live in a 1920s 1.5 story house that apparently has some sort of metal structure in the wall that for years has created dead spots in my house as far as WIFI is concerned - if the Shaw modem is on the main floor, I don't have reliable WIFI in my basement home office; and if the modem is in my office, there are dead spots on the main floor and really poor connection for my daughter in her attic bedroom. 

I have Shaw 300 and got pods to try to extend WIFI's reach, to no avail.  I'm now thinking that the only solution might be to simply add a second modem/internet account for my home office, but that will add significantly to the cost.  So before I do that, and being the tech idiot that I am, I want to ask this question:

I have a coaxial outlet in my home office.  Could I get another, third party modem/router to plug into it, and then connect that to my office computer with an ethernet cable?  If I do that, how will that device interact with Shaw's modem (or maybe it won't)?  

I'm tired of paying for internet service that I'm simply not getting.   This is so frustrating. I'd really appreciate any advice you can give me.