First, you said "upgrade my wifi" but then say you plugged into Ethernet and got the 100/10 performance so I assume you mean the ISP (Internet Service Provider) download/upload limits your plan has?
Anyway, wi-fi is limited by the performance of either the wi-fi adapter in the PC or the router/gateway unit's wi-fi capability. That is also affected by interference by walls/ceilings in combination with distance from the router.
What performance do you get just a FEW FEET from the router without any object in between the laptop and router?
Also you said:
"before the problem started I would get wifi speeds of 60 down and 5 up"
What problem do you mean? You don't state any values lower than this so your performance was that but is now lower?
I'm still not clear what you mean by the wifi "upgrade" though. If you simply got a better ISP plan that should not reduce wi-fi performance. It should either get better or stay the same (depending on whether your wi-fi bandwidth between your PC and Router is fast enough to keep up with the Internet connection speed).
When you say "100" do you mean to say you run SPEEDTEST and get 100Mbps (12.5MBps) download performance?
If so, I know cheaper wi-fi devices are roughly 3MBps to 7MBps, and good ones are 7MBps+ (depending on router, whether it's 2.5 or 5GHz, distance etc).
So 40Mbps would be 5MBps which is about right for many laptops probably.