Try Nick's Atmega Fuse Calculator:http://www.gammon.com.au/forum/bbshowpost.php?bbsubject_id=11653
It is the same SPI hookup as the Arduino as ISP and it also has a 8MHz that comes out of D9 that you can plug into the Target XTAL1. See where your fuse bits are set.
Adafruit has an improved ArduinoISP sketch that you can use with the same pin/D9 to XTAL1 to get your bootloader onto the Atmega using the Arduino IDE.https://github.com/adafruit/ArduinoISP
After you are comfortably bootloaded, we'll check out the USB2UART again.