Wireless connection stuck at 5.5 Mbps

I have a D-Link DI-624 router I recently purchased for use with my TrueMobile 1300 contained in my Inspiron 8600.  I cannot get the laptop to connect at 54 Mbps for nothing in the world.  The top connection speed I can get is 5.5 Mbps, and I can be no more than 5 feet away from the router.  I've tried everything I can think of:

 

- Used all the default settings on the router

- Reset the router numerous times

- Changed channels

- Turned extended range on and off

- Turned 802.11g mode on and off

- Turned SSID mode on and off

- Turned off the Super G mode

- Tried it with and without WPA-PSK encryption

- Tried both dynamic and static DHCP

- Used MAC filters

- Used both WCZ configuration and the DELL WLAN Utility

- Uninstalled the drivers, took out the wireless card, rebooted, turned off computer, turned computer back on which found the card, and used the Windows WCZ to connect

- Reinstalled the DELL WLAN utility

 

Nothing seems to work.  Did I forget anything?

 

The computer connects just fine, but then it steps down from 54 to 5.5.  I have tried a friend's laptop, and computer connects and stays at 54.  On top of that, she has an Atheros wireless card in her computer, so it connects and stays at 108 in Super G mode.

 

I've never tried the computer on another 802.11g network, but I seem to have no problems with 802.11b networks connecting at 11 Mbps.

 

Thanks in advance for any suggestions!