Laptop wifi trouble, please help?

[ohohoh]

Last week I got my laptop fixed. I used to get a good signal upstairs from my wifi, about 3 bars. Now that I've gotten it back from the shop, all fixed, I only get 1 bar and it's impossible to use. Nothing has been changed with regards to the wifi, and everything else is the same. Can anyone think of any reasons why this is happening, or any way I can boost the wifi signal upstairs?

[KiddSpecs]

What u can do is get those signal boosters from argos or other shops they do quite a good job abd arent that expensive, just type in wifi signal boosters

[mich. .]

Take it back and tell them they forgot to plug in the antenna.