My down/upload speeds on a wireless laptop are slow

I have two laptops. An HP G60, with an AMD TurionX2 at 2.1ghz/4gigs ram/running Vista 64bit. It has an Atheros wireless adapter b/g compatible.
The other laptop is a Compaq F700 with an AthlonX2 at 1.9Ghz/2gig/running Vista 32bit and a broadcom b/g wireless adapter.
The laptops are sitting side by side on the sofa, about 15 straightline feet from the wireless router which sits in the basement.
I just ran the speakeasy speed test.
The HP G60 gets a 15,500kbps download and 2900 upload.
The Compaq is only 983kbps down and 250 up.
My provider is Comcast and I supposedly have a 6mb line.
I checked both drivers and they appear to be the latest available.
Can I do anything to the Compaq to speed it up?
Thnaks..