Argh, gutted, wrote long post and it just disappeared. @Lightkeeper - I might have been living across the road from my DH's grandmother 
@ConfusedWife1234 - I think I can relate (similar background story + west German DH who seems to always dress effortlessly yet perfectly - it's cultivated over years actually, I've got his teenage photo albums to prove this
) - feel free to PM me as I totally get your problem!
I do agree with previous posters though re: there is much more to this than clothes. There is a confidence problem and that's actually what gives you away as the "outsider" NOT what you wear. Generally-speaking, people sense fear and lack self worth in the person they are dealing with - there are lots of signs you are probably not aware that you're giving out, but they are not your clothing as such (and even if clothing is part of it, it's a very very small part - in other words, you will still stand out even if you wear the "right" clothing).
Add to that the typical Eastern European stigma about psychotherapy or anything even vaguely suggesting a mental health issue (which confidence and self worth comes under) and you have the perfect shit-sandwich that you're stuck with.
Try reading these:
Women, Work and the Art of Savoir Faire by Mireille Guiliano
And
A Guide to Elegance by Genevieve Antoine Dariaux
Both are French women, but the advice is applicable across Europe as it gets to the basics. They will probably save you a few hundred euro in teaching you how to find what clothing style works for you. More importantly, they focus a lot on feeling comfortable in your own skin.
After you've read them, it will be easier to work on confidence and feeling of self worth - you don't want your children to be victims of the same problem you have. You will probably need outside help (e.g psychotherapy or similar - sorry I'm not sure re: German terminology) and it will take months of self-work to get there, but it's absolutely possible to do that!!!