Your Bachelors degree probably won't bring you much over here - you need a masters or (preferably) a diploma to be considered as being "graduate-level".
Having said that, if your German is fluent then the best chance of getting work quickly may be in the service industry - Aida cruises would seem an obvious internationally-focussed company in Rostock that might need bilingual staff. Otherwise, there's always adverts for jobs in call centres being advertised.
General sites for finding jobs:
http://www.mvweb.de/job/ (ads from the "Ostsee Zeitung") and of course
http://www.arbeitsagentur.de/ (official Arbeitsagentur site), but I guess you already found those.
Sorry, probably not the answer you're looking for, but without a skill other than being able to speak English, and with only a Bachelors degree, you're going to find it hard to make your USP clear in the job market.
As a tip - if you're willing to travel around an hour and have a car then you can get a long way west in that time - Lübeck is only very slightly over an hour away (less if you drive really fast since the A20 is unrestricted and hardly at all congested), so might be worth looking for stuff around there as well.