I assume you've already rooted via motochopper as that's a prerequisite here.
I prefer to push system files via adb but that's slightly more complicated so here's the root explorer method.
I suggest ROM Toolbox Lite, which you can get from the Play Store-- it contains, among other things, Root Browser and Rebooter.
- Place my modified LGSystemUI.apk on your SD card or internal storage download folder (if you download on your phone from this thread, it will be in /sdcard/download and you can long-press the ZIP file and Extract)
- Find it using Root Browser-- external SD card is under /storage/external_SD, internal storage is under /storage/sdcard0
- Long-press the downloaded LGSystemUI.apk and select copy
- Navigate back to /system/app
- Select 'paste', select Yes to overwrite
- Press back until you're at the main ROM Toolbox window
- Scroll down to rebooter, select Reboot
Let me know if you have any issues with this, as I said it's not my preferred method, but getting adb set up properly if it's your first time using it is a whole other beast