[Tru2Chevy]

He has a wireless router.

Ok, let me see if I get this all straight.

The router is in your sister's room on the second floor of your home.
There is a wire run from the router into the basement of your home for your father's computer.
There is another wire that runs from the basement to your garage, which is detached from your house.

If this is all correct, then there is a simple solution. Buy a small switch (4 or 8 port, they are relatively cheap). Hook the line that runs from the router upstairs into the basement into the switch, and then hook the line from the garage into the switch as well. Then you will just need one more line to run from the switch into your dad's computer in the basement.

- Justin