How Do I getg the Max Speed from my internet?

Hi I am running a Acer Aspire 5315 Laptop with Windows Vista Home Basic, and Our internet connection is Qwest 20mb/s I am on a wireless network. The thing is, I tested the speed periodically and it only runs around half that speed... Is there a setting on my laptop I need to set or what???? I know we have the right router because or Service Provider told us it was...I will give details on it later when I get up later... I would like to speed up my net to what it is supposed to be running, also what would be the settings for windows 7 because my wifes laptop runs around the same speed... I tested my speeds when she was asleep so there would be less drain on the speed...

If I could get help in this matter, I would be greatfull.

Thank YOu Very Much Foe Your Time