General :: SGSII - Maintaining WhatsApp Conversations

I have a SGSII and recently i switched from the official ICS rom to CM9 (build date 20 april). I expected to get a better battery life since CM9 is so populair. Unfortunately this isn't the case and so i want to switch back. Only thing is, last time i switched, all my whatsapp conversations were blanc. I couldn't retrieve any old conversations. I know you can email the conversations to yourself but that's not what i want (or is it possible to use these emails in some kind of way to get the conversations back into whatsapp???). Is it possible to backup all my conversations so i can put them back into whatsapp after i flashed the phone to another rom (probably the official rom).

Also, as you can see, I'm not fond of CM9 although this is the most populair rom. Did i do something wrong? I'm a heavy whatsapp user and even when i'm charging the battery drains when using whatsapp (brightness auto and stable WiFi connection). I never game on my device or use bluetooth or gps. I mostly use my phone for facebook, whatsapp, twitter and browsing. Also my phonesignal drops sometimes and my 3G is also worse than before.

Is there a ROM which will give me with my requirements the best Battery life + phonesignal (3G)??