Low internet speed when using Nokia N72 as ...

hello im puneet and im using Nokia N72 mobile phone as USB modem(OTA). The network service provider(GPRS) is Airtel India. they said its a broadband connection and its connection speed is 460.8 kbps. im using both Mozilla Firefox and IE web brousers. i've heard htat the broadband connections are very fast but im getting only 4kbps download speed from all sites. is there anything wrong with internet service or is it true that the maximum download speed depends on capability of my mobile to recieve and transfer data from server to itself or pc? if yes then what phone models do support 40-60kbps download speeds?