If your hardware is capable of 1Gb/s speeds configure it as such. Hardcoding the nic and switch to full duplex is recommended as this essentially doubles your bandwidth and if you can do so you should with the speed at 1Gb/s. You could leave it to auto-negotiate although this is typically frowned upon for reasons I am unsure but apparently having nics operating at varying duplex is a bad thing.

Ignoring the details replacing those hubs irregardless of your nics configuration will prove a drastic improvement.