Thanks for posting on the community. It's nice to have you here.
Sorry to read you are having an issue with the wireless signal.
Have you tried to change the wireless channel just in case there is interference within the property?
If the signal has far to reach it may be worth thinking about power line adaptors to boost the signal upstairs.
Let us know how you get on
New around here? To find out more about the Community check out our Getting Started guide