|You network interface card has absolutely nothing at all, not the slightest effect on what you download speed from the internet, is.|
A Network Interface card has a maximum bandwidth of 100 Mbs a second, way, way above anything the Internet can throw at it. Even an 801.11g Wireless adaptor has a maximum bandwidth of 54 Mbs second. Still way above your 16 Mb maximum.
If you are only getting 1Mb then you should be banging on your ISPs door. The problem is elsewhere, not with the network interface card. It could be that because you are doing a lot of downloading your ISP has put a cap on your bandwidth to preserve bandwidth for other users.