My internet keeps going limited?

[Dillan]

Me and my downstairs neighbour who is 85 share internet. She brought her friend over and she brought her laptop, when she got here my internet kept going limited. I thought it would be better once she left but it hasn't improved, my downstairs neighbour doesn't undertstand much about computers and when I asked her if I could unplug and re plug in the router she wouldn't let me and thought it would ruin internet for her and was unable to understand that it wont.
I have windows 8 My internet is usually ok with some disconnections when im browsing the web. However when I play league of legends, or hearthstone or just try to download something (tried downloading windows 8.1) it just goes limited instantly and I have to keep reconnecting. Is there a wy to fix this without having to touch the router physically? can I do something wirelessly?

Ive tried to connect to my router over 192.168.0.1 but the router seems to not be on default password or username. Any help would be appreciated this has gone on for a week now.

[bonti]

O SURE YOU CAN.......REMEBER TO BE KIND TO THE AGED AND TALK THINGS OVER FIRST .....KEEP THE PEACE!

[Boss]

Maybe it's something to do with your ISP.