Question [Q] A System War over my S3

So um.......where do I start? My s3 just got drowned by the cold water from the cooler that poured into my pocket which my s3 was as I was picking up my bags from my car. I did put my phone and the battery out and put into the full pack of rice to suck up the water out. After few days, It started to work again until this month. My phone is starting to get super weird and crazy, it shut off on it own and never turn on after 30 mins. Then when I lock my phone, it start to freak out, lag, shut off, turn back on for 5 sec., and shut off again.

Also, my phone is running on official OTA JB update and task's rom too. (I tired the other ROMS to resolve the problems like stock ones and it is doing the same thing too). Does it means that I have to get new phone because of the system got mess up?? :/

Device that I am using now?
~AT&T Samsung Galaxy S3 with Marble White
~~Task's Rom: AOKP

Preview AT&T Phones:
~Motorola V190
~~Pantech C150
~~~Samsung Mythic
~~~~Sony Ericsson Xperia x10i with Jelly Bean (Dead)
~~~~~~iPhone 3GS with Jailbreak (few weeks)
~~~~~~~Samsung Galaxy S3 with Marble White (Drown by water)
~~~~~~~~iPhone 4 (few months)
~~~~~~~~~Next Android Phone?