I'm not sure what to do here. I got an interview in a week and this position I applied for a month ago asked me to come in for an interview. I changed the format of my resume in that time and added a few things to it. Should I just print out the one I submitted to the company? I don't want them printing out my old one and I bring my new one.
Bring the new one, and hand it to them at the start if the interview, explaining that you think the new one is more informative and easier to read. Nobody will be surprised; it is pretty much assumed that people continue to fine-tune their resumes.
Don't be surprised if they continue to base the interview on the version they have had more time to read, but if they ask a question that is civered in the new version of the resume you can mention that in the course of your answer.
Unless you think that the new changes to the resume would really improve your chances of landing the job, I would just take the version that you submitted to get the interview. That version was good enough to get you the interview and they've already studied it and may have developed some questions based on it. Throwing a whole new version at them when you sit down for the interview may not make them happy or it could throw them off - or they could just ignore it. Better to not take a chance.
That being said, if your new one has some extra stuff on it that you feel could be of use then bring one of those as well as the old one. If it comes down to "hey, we like you but you just don't seem to have enough experience with X", and you have that experience on your new resume then you could bring that out and point out that you do have that experience and you have updated your resume to reflect that.