Ethernet Cable Per Foot Why Is My Home Network So Slow?

Why is my Home Network so slow? - ethernet cable per foot

Hello, I have a wireless network at home, which is connected to a storage device (Network External Hard Drive).
The configuration is as follows:

DLINK wireless gateway (the router is configured as a bridge connected) with my hard drive with the wireless gateway and wireless ADSL Gateway with a cable modem is.

for some reason, when transferring data from my PC to the external drive, I was incredibly slow transfer rate. For wireless, I was lucky if I get 1 MB per second - but is generally around 600 kb per second. And even if you connected the Ethernet cable (to the wireless gateway) are still struggling to get 5 MB per second.

Windows reports my speed to 54 Mbps wireless network and the speed of my connection to 100 Mbps. Both the bridge andLaptop in the same room - a few yards away. I also updated all my network cable Cat 5e Belkin, if that was the problem, but has little help.
Can anyone suggest what is to me the problem, or I like to find the cause of the problem?
Thank you!