is it possible to get a part time job while studying there?
Let's answer this one first. It's extremely difficult, and near impossible, to find any work as a foreign student in Poland. Make your plans on the very safe assumption that you will never earn a single penny during your stay in Poland. If you can't pay for your studies and living expenses without a job, then forget about studying in Poland.
International Business
It's useless to study international business anywhere except at top schools like Harvard or London School of economics, and even then... It's one of the most worthless things to study.
Don't waste your time and your parents money studying something useless that will not help you on the job market. This includes most business and economics-related subjects. Far too many people study these majors, and international business graduates are as common as cockroaches.
Instead, study something useful, math intensive and in-demand like financial engineering, financial mathematics, actuarial sciences or econometrics. Or study a good engineering field like petroleum, geological or biomedical engineering.
And do it either in your home country, or in a rich country with lots of R&D dollars, not Poland.
Sorry, but Poland is generally not the best place for foreign students to study. And "business" majors are just about useless.