@Matthew1 

Do you mean the VR600 is downstairs, and the computer is upstairs, where the signal from the VR600 is weak, and you want to add the Archer T2U Plus to the computer to get a better signal?

We actually cannot guarantee you will get a better signal from the VR600 modem, as this T2U Plus adapter is only a signal receiver, we can only say it has better gain than standard wireless adapters, you may get a better signal. However, if the obstacles or walls in your house eat off the signal a lot, it may also fail to connect as a good reception.

If I were you, I may consider getting the powerline adapters instead of the wireless adapters, you may check if the powerline adapters can match your requirements:

https://www.tp-link.com/home-networking/powerline/

https://www.tp-link.com/home-networking/powerline/tl-wpa4220-kit/