have you tried any of the internet connection tweaking programs , such as
'cable nut' 'tcip optimizer' 'internet tweak 2000' etc..
on some computers they can make a difference..
is it possible to change the speed settings of the interface? USB ? that connects the adapter box to the laptop
and have you compared your setup to anybody using a cingular cellphone cable to their laptop, working from the same location as you..
if possible I would try out their phone on your PC and let them try your card adapter system on their PC
also some phones, such as my LG 8100 from verizon, have PC connection speed settings in the phone setup menus
if these are set to 19k or 34k , it is NOT possible to get full high speed NO matter what the other software is set too
check the software setups for the aircard itself, NOT just the windows modems settings,
do you have management and setup program for the aircard ?
NOT the connection program..