I would get an aerial with a Signal Booster.I bought one from Argos several years ago & thanks to the Signal Booster which came with the aerial.It was a big help.
I never find signal boosters make any difference, I have tried several. In our kitchen it is impossible to get a good picture and nothing seems to work, even cabling an aerial along the top of the wall cabinets to place the aerial next to the window doesn't do it. We have to move the aerial evry time we change channel.
My experience is the same as Dudley's. It's just as cheap to pay roughly �8 for a proper aerial from Argos and place it in the loft(no need to put it outside) via a small hole in the ceiling then tidy it all up with a bit of cable trunking.