Best way to extend wifi range?

[TheSteveMilliband]

Hi. I'm looking for some tetchy advice, and thought I'd ask wise mnetters. I have a pretty old router upstairs with pc and which works pretty well through the house but would like to extend it so can get wifi in the garden. There is a telephone point and electric socket by back door. Would I be better to
A) get a wifi extender
B) shell out for a more expensive wifi power line
C) buy a new router for upstairs and use old one as a 2nd by back door (don't know how easy this is)
TV is by back door too, so might be good to have an Ethernet connection but works ok without so not worth shelling out a lot for
TIA

I asked DS this as he was in the room - I am not techy whatsoever. He said:

How good is the wifi connection by the back door, if you intend using a wifi repeater unit with no hard wired connection? It needs to be decent strength. Use Wifi Strength Connection app on your mobile phone to see signal strength.

Thank you Donkeys (and Donkeys DS) . Reception is not dreadful but not great - but our routers pretty old so may get new one and try to use old one downstairs. Have moved router downstairs for now and working great except can't now use PC (dinosaur which doesn't have wifi so needs Ethernet connection to router!)