apple IDs

I have an apple iphone 4s. It is my work phone (I puchased the phone-work pays for the plan). Work has me using my work e-mail address for the apple log in, I think because they wanted to make sure my phone would always be able to be updated through a strong internet conection. I just purchased an ipad 4 to use in place of a laptop. I set it up with the same apple id, my work e-mail. Now my ipad has my work stuff on it. I do not want this! How do I seperate my iphone from my ipad? Can I change my apple id to my personal e-mail address? I have wireless at home, which allows me to update just fine. Dont really want to maintain two seperate apple IDs.

Thanks!

Joe