HTC Solutions near Hotel Dieu has a Riff Box for JTAG. I've seen him use it.
The fee would cost around $80 to unbrick the device, assuming the unbricking is successful.
If you want to solve it by yourself, there's a cheaper method, and you'd learn along the process.
You need to check if the device's JTAG operations are supported on an Arduino (Uno). Download the code for the operation, and upload it to an Arduino (purchased from Katranji for ~$15 if you're a student).
That would save your S3 plus allow you to unbrick further on. And you'd learn and you could do it for others.
Plus, the amount of projects you can do with an Arduino are endless by themselves.
http://www.arduino.cc