Arduino doesnt work - pls help

Hello,
I damaged both 328P and 8U2 bootloaders on my Arduino when I accidentally unplug USB cable when I was uploading a program into my Arduino.
It looks like I successfully reuploaded bootloader into 328 but I cant still reupload 8U2. I dont know what to do with it now.
Please, can somebody help me?
Any help will be appreciate.

http://arduino.cc/en/Hacking/DFUProgramming8U2

Thank you for reply johwasser. My PC cant detect Arduino, no sound is played when I connect Arduino to PC. I cant use Flip to upload hex into 8U2... I soldered another ICSP pins (close to 8U2) to my Arduino and I tried to upload hex through it but unsuccessfull.