alltel aircard

Okay, I have a Huawei EC168 aircard i got from alltel before the merger. when they switched over my local network, the card wouldnt connect anymore. after 3 days and about 5 combined hours talking to tech support and people at my local verizon store, I finally got the device to connect again. It works but its slow... REALLY SLOW..... seriously my dial-up was probably faster...any idea on how to straighten that out? I'm in area code 31503 Waycross, GA.