Building a Better Network

10mbit is your cabling? = Cat3.

You want to be running at least Cat5 in your situation. Cat5 will give you near the best performance. If your router is relatively new as it seems, you should be in good shape there. May need to update the firmware to make sure its working at its peak performance.

The wireless will be slower regardless.

When doing major downloads, your limiting factor is your internet connection and your router. If you have 7mbps, even so your router is probably a 10mbit and won't realize the 7mbps connection.
This is the situation I have at home myself.

Anyhow, cabling should be Cat5. Router should be a 10/100mbit.

Also, when downloading 3 files over your cable modem, one file will gain more priority over the others but you also have to split your bandwidth 3 ways and you will get slow downloads.. thanks to the limitations of your router and internet connection.