If you're talking domestic law school GPA, then while a 3.0 is low, it's not an app killer unless it also ranks you very low in your class. I've heard of folks being admitted to NYU LLM programs (not necessarily International Legal Studies) with GPAs in the low 3s but I think their class rank was still pretty good and they had other strong factors (work experience, journals, etc.).

It's really hard to nail down what the admissions criteria numbers are because there are so many soft factor involvements in LLM applications. If you are intent on applying, can you speak to someone at your law school for advice, perhaps the professor from whom you will request a recommendation? They might have an opinion on the admissions standards for students from your school based upon past admissions.

Barring that, it may be in your best interest to hold off on applying while pumping up your soft factors or simply applying with a realistic view towards your chances (assuming you can afford the app fee comfortably). You may only have a very slim chance to get in with a low GPA, but you will 100% not get in if you don't try.

Unfortunately, I don't really know much about the specific reputations of too many Public International Law programs, so I'm loathe to advise you on specific schools for fear of leading you to a bad choice. I noticed that you are strongly considering some European programs and I think that will be a wise decision for you and may help your marketing since you have excellent foreign language skills and speak fluent English.

Do not worry too much about your GPA at this point. Do as well as you can, but as you noted, it is not likely to rise significantly in the final semester. Besides, despite it not being a high raw GPA, it may not rank you as low in the class as you believe it does. At some law schools, a 3.0 is quite near the median. You never mentioned your class ranking, so you should definitely find out what it is before making your application decisions.

Also, I notice that you have mentioned repeatedly that you do not wish to "waste" a recommendation letter. You should know that for many US programs, the recommendations must be given via email and though this means the recommender does need to do extra work for each added school, it is largely copy/paste work. If you do not apply to too many schools overall and you have willing recommenders, it is probably not too much of a burden to ask for a couple of extra submissions on your behalf. The difficult part for the recommender is actually composing the recommendation.