I don't actually do either degree, but I do know a few people who do them. Unfortunately, I can only really give you a rudimentary answer to your questions for various reasons:
First of all, it is a requirement of International Studies that you study a language, so in this respect they're not all that different. You'll have core units that are compulsory, and usually centre around the language of your choice. I know UNE offer French, Italian, German and Mandarin and possibly a few more. You'll also be studying Linguistics units, so I recommend you jump on the UNE webpage and take a look around for unit descriptions (I only vaguely know where they are as the layout changed recently). Anything with the LING prefix is a Linguistics unit. I don't know much about these other than that they exist (and where the lecturer offices are as they're on a shortcut I take to get to a tutorial every Wednesday). I believe you'll also study Sociology, at least at an introductory level. Be warned, however, as I am told it can be very difficult. The best way to investigate this would be to find a Course Outline handbook from the Faculty of Arts as it will tell you all of your required subjects. You may also want to consider an International Business degree, which combines languages with business, but frequently has clashes in its timetable ...
Careers-wise, I know even less about what you're asking, largely because the people I know who are doing these degrees are largely first- and second-year students. However, UNE has a dedicated careers advisory service, and they're excellent at what they do (trust me, I was up there the other day). They also run two things which may be of use to you: the WORK300 unit which can be done in third year or above, which allows you to gain 120 hours work experience through your school (schools are sub-sections of a faculty, not your actual school; mine is the School of English, Communication and Theatre). The second is a course they run in your penultimate year of study that allows you to search for a job while you study so that you can walk straight into it once you have graduated.
HOWEVER, I have to warn you, I don't know much about anything I have just posted, and it's a very real possibility that I am wrong, so don't take it as Gospel.
! Or stuff I already knew. Which isn't much.