Wifi Booster/Repeaters

Hi… I was wondering if one of these would help me and knowing there are quite a few tech savvy members here I’m appealing for advice…

I’m on Sky broadband and TV. The router is on the 1st floor back bedroom (my man pit) and the TV in the ground floor lounge at the front of the house, with the TV running off Wifi. Things were fine for a while after installation but lately I have been getting more and more buffering and dropouts on both TV and internet in the lounge (for some reason Youtube is particularly affected) but not on my PC which is on a direct cable (Cat45??, Cat5?? – I dunno) connection to the router. Often my wife has problems logging on to internet on both her phone and tablet (both recent Samsung items) whereas I am OK on my phone but have the same issue with my tablet.

Someone who purports to know about these things has suggested the the distance between the router and the lounge along with it being on a different floor is the issue so I am wondering if a Wifi booster will do the trick as laying in a cable connection is impractical? Sky have said that their router is functioning properly and their helpdesk seems to concur with my pal’s conclusion but they wouldn’t commit themselves on the question of Wifi boosters. Any thoughts from the knowledgeable please?

As always many thanks in advance to all who can help.

Rob