B,G,N Adapter with 802.11bg Router

Hi, first time posting and any help is appreciated. Here is my scenario...

I just purchased a laptop for my Mom and we are having significant reception problems on my home network.

I have the following hardware:

Router = Linksys 802.11b
My Laptop Adapter = Atheros AR5007 802.11b/g
Mom's Laptop Adapter = Intel(R) WiFi Link 1000 BGN

Per Speedtest.com:

My Laptop = Upload of 4.21 mb/s and Download of 2.45 mb/s
Mom's Laptop = Upload of .31 mb/s and Download of .26 mb/s

My Laptop runs Windows Vista and Mom's runs Windows 7. Both show full connectivity (all green) on network bars.

Do I need to purchase a new router or should I be worried that I purchased a lemon (Best Buy)?

Thanks in advance,
MFAM