Google has pushed out the 2nd Android 4.3 for this year on both the original Nexus 7 and New Nexus 7 (2013). You can unroot and do the updates yourself (which is time-consuming and you will have to re-root) OR you can simply grab rooted version of these firmwares as a ROM zip file and install easily using TWRP recovery.
So, grab them here!
Download Latest rooted stock ROM for your Nexus 7:
Latest Nexus 7 Android 4.3 JWR66Y ROM with root (This for original Nexus 7)