I2S where can I get a I2S bridge in the U.S That plugs into computer slot ?

If I were you I would go for a J Play usb card instead as I have a Ps Direct Stream Senior Dac and I have tried it with I2S and My usb card. The card wins hands down between the two on my system . It is easily installed and and does not need you to surf for drivers but does benefit from a linear power supply. If this is not agreeable to you I apologise and you can resubmit your question. 

Myself and friend had the jplay card it broke within 18 months and no warranty honored , the Denafrips Iris Night and day better sounding totally cleans the incoming digital signal many steps for cleaning including opticouplers,which are light what doesnot transmit noise then goes out to I2S hdmi or other outputs .