yeah, without going into too much detail the data packets you receive and send are divided into sections. Obviously a large porion of it is the actual data you want (e.g. this forum page) but along with that is other info such as the source and destination ip address so that when the packet is travelling along the network each router it comes to know where it has got to forward it to for the next hop. That is just some of the info and that obviously takes up some space.
I assume the problems you are having are speed related. Have you got a pc or a laptop? If you have got a pc you are going to have to get a usb nic, if you have got a pc you can go for the same or get a pci card which you can pop into your pc which is far much better in the mong term. Something like this would be good.
http://www.amazon.co.uk/TP-Link-TG-3...ds=gigabit+nic