"Camera can't connect" and good longer battery upgrade from S3? topic

1. My "camera can't connect" error message came up. Tried the usual..uninstalled flashlight programs, checked to make sure no other program is using the camera, forced stopped, cleaned data and cache, re-installed google apps, waiped davlik, fixed permissions, upgraded etc etc. Nothing worked. Weird thing is that 'open camera' off play store works fine, but google's camera doesn't. No apparent reason for this to happen either. Any suggestions?

2. I love the feel and size of my S3. Great for running. Easy to unlock and put a ROM on , underclock...what is the longest battery life upgrade I can add to this on an AT&T contract?