Holly,
Switches are no problem. Ratshack has plenty. For $300 I probably would have gone for an airport express and wireless card for the PC and a passive analog summing box (RCA connection box with resistor network to couple analog outputs)...for the same money it would give you more flexibility (connect to any system in your house). The express has a pretty good D to A and excellent range. (Disclaimer: I have Mac's at home ...so I am not sure how easy this is to do on a PC.)
Switches are no problem. Ratshack has plenty. For $300 I probably would have gone for an airport express and wireless card for the PC and a passive analog summing box (RCA connection box with resistor network to couple analog outputs)...for the same money it would give you more flexibility (connect to any system in your house). The express has a pretty good D to A and excellent range. (Disclaimer: I have Mac's at home ...so I am not sure how easy this is to do on a PC.)