Looking to upgrade to AppleTV3

I have been using an AppleTV2 with Firecore software for the past four years with no issues.  I really enjoy having access to my movies and TV shows on multiple external harddrives that are connected to my Airport Extreme tower. 

I am really interested in upgrading to the AppleTV3 to get access to 1080 resolution but I hate that I won't be able to use Firecore's software to navigate my media.  (And looks like a jailbreak is never going to happen for the AppleTV3, no matter how much I wish for it)

What options do I have if I indeed do upgrade to the AppleTV3?    Most of my media files are AVI, MKV and MP4.  I know I can convert them, then import into iTunes, but that is a major pain in the ass.    Does the new AppleTV3 have the ability to read files from an external harddrive that is on your LAN ala an Airport Extreme device?  

Thanks for any advice, 

Chris