Configure the wireless connection speed

Hi,

I need to change the connection speed of my wireless network from 54
mbps to 36 or 24 (to test if it increases the reliability of my
wireless connection). I changed the setting in my D-link router to 36
mbps but my vista pc still shows the connection at 54 mbps.
Is is possible to force the vista to connect at 36 mbps to wireless
network instead of full speed.

I will appreciate your help

Regards,
Amir