That seems a very complicated setup for something which may be a lot simpler.
Why don't you just connect the Quadra via an ethernet cable to your wireless router? This works with both my Q650 and Q700. I use static IP addresses. If this doesn"t work, then try the more complicated setup.

Click to expand...

I would try that except my wireless router is upstairs with the house's main computer. The powermac and quadra are downstairs and the powermac is using an airport card. I could use airport express like someone stated earlier, but the two ethernet cables and hub would be only $20, while the alternative would be well over $50.