You need a battery tender.
These cars are battery hogs
They are constantly drawing power even when parked.
You fit the driving profile where they are likely to deny you a new battery unless
there was a recall on a batch of bad battery which there have been to you might check.
A Ctek 3300 battery tender is one of the better ones used here.
Also yes get an aftermarket battery and get an Indy to register it.
If you don't already have and AGM battery, and most cars don't ,just get a battery with the form factor CCA and amp hours close to what you have . I got a Interstate MTP92R/H8 it was 240 installed from my local Indy .
the above link tells you why there is so much power used by the ibs
Also locking the doors and getting the key fob away from the car will cause it to go to sleep more quickly
an save some current draw on the battery.
Read this one it will give you and idea of the magnitude of the problem
Last edited by ctuna; 12-01-2012 at 12:37 PM.