This assumes you have your bootloader unlocked!
Download the drivers for your phone if you don't have them already:
http://forum.xda-developers.com/attachment.php?attachmentid=1191669&d=1342028159
Plug your phone in and install from the location you unzipped the drivers to.
You'll need the ADB/Fastboot utilities from here:
our forums' mini-sdk
Download stock recovery for IMM76K:
recovery.img
I just personally pulled it from a factory image so I know that's the one.
Download cwm from:
http://download.clockworkmod.com/recoveries/recovery-clockwork-5.5.0.4-toro.img
Download the lastest Superuser from:
http://downloads.noshufou.netdna-cdn.com/superuser/Superuser-3.2-RC3-arm-signed.zip
Extract the SDK tools. Place the recovery.img, clockwork-recovery-5.5.0.4-toro.img and Superuser-3.2-RC3-arm-signed.zip with them.
Open command prompt at the ADB location. You can easily do this by shift-right click inside the folder and "Open command window here."
Type:
adb reboot bootloader
Verify your phone drivers are installed again, this time for fastboot.
Type:
fastboot flash recovery recovery.img
Highlight and enter recovery as normal to make sure it took the flash.
Once in recovery type:
adb reboot bootloader
If you still had cwm, re-flash the recovery. If you had stock recovery again then continue on.
Type:
fastboot boot clockwork-recovery-5.5.0.4-toro.img
This should bring your phone into clockwork while keeping stock recovery.
Flash the zip for the update just like you were before. When it's done, reboot the phone and make sure everything boots perfectly.
Now we'll get your root back!
Put Superuser-3.2RC-arm-signed.zip on your phone.
Type:
adb reboot bootloader
Type:
fastboot flash recovery clockwork-recovery-5.5.0.4-toro.img
Now enter recovery, flash Superuser-3.2RC-arm-signed.zip and reboot the phone.
Sometime you might have to flash cwm a couple times in order for it to really stay. Let us know if that's the case!