The answer to both questions is yes, but how much it will improve the wifi is another question.
But first of all I would check your internet connection by connecting a device directly to the hub to check that there is no local circuit impediment causing the connection to drop. (assuming you do not have any devices staying connected when your laptop looses connection)
Wireless reception is affected by many factors like Range, Client hardware, the Topograpy of your home, and the big killer, Wireless interference. As you can see, there are many variables so specific advise is almost impossible from the remote location as the forum.
First of all, I would try to optimise your wireless sgnal
I would ensure the Hub is placed in a central, open position, as possible, away from obstacles and electrical devices.
You could try changing the wireless channel manually. Downloading a wireless scanner like InSSIDer for Windows or WiFiAnalyser for Android would help by showing you the surrounding wireless networks, the channels they are broadcasting on, and their signal strengths, so you can select the best wireless channel. Bear in mind that the wifi scanner will not show interference from other sources of wireless interference such as A\V streaming devices, Baby monitors, Chordless phones, Microwave ovens, Plasma TVs, Security systems, etc.
Setting the Hub's radio setting to 300Mbps (or 40Mhz channel) is not advised on the 2.4GHz band as it takes up over half of the available spectrum, making it prone to wireless interference..
Using the wider, usually less congested 5Ghz band could help, if your client devices support it.
Once you are confident you have optimised the signal as much as possible and the wifi is still poor, then extending your wireless network would be the next step.
A lot depends on what wireless adapter you have.
You do not specify which model of the Netgear WNR3500 you have, I will assume it is the V2. This is a fairly old router now and supports the draft N wireless standard. Whilst you can improve the general wireless coverage in your home by putting the hub into modem mode and using a decent third party router toreplace the basic wifi performance of the entry level hub.
However, the Netgear WNR3500 is a 2.4Ghz only device so any 5Ghz devices will not benefit from the wider 5Ghz band. It might prove useful as 2.4Ghz wireless access point to improve 2.4Ghz wireless reception in an area of your home. You can do this by assigning a static IP for the Netgear and disabling it's DHCP server.
The alternative as you said would be to get a decent powerline adapter set to improve wireless reception in hard to reach places. I would bear in mind that actual speeds will be around 15 - 25% of advertised, and will be dependent on the condition of your electrical circuits.
Thank you for a very comprehensive view of the matter.
one thing occurs to me - is it possible that replacing windows 8 with windows10 on my desktop has had an effect? I don't think I was having this problems earlier before I upgraded. Perhaps windows is trying to make me use them and not Google.
There was a bug in Windows 10 that turned off the wifi on some wireless adapters, this was resolved by disabling the wifi adapter and re-enablingI haven't seen this issue for a while so it could have been resolved by a Windows Update.
it. It would be worth running the Windows Troubleshooting Tool when you loose connection, it can somtimes resolve Issues.
It would be well worth checking that the wifi adpter in the laptop has the latest drivers, especially a Windows 10 specific driver if available. I would check the wifi adapter's manufacturer's website rather than relying on Windows update as it is usuallly unreliable.
I am not sure what you mean by what Windows is trying to make use of, rather than Google.