Dear Sir/Madam, if you are interested in increasing child support in court, you must sue a person who is obliged to support a child (usually a father). According to the Polish law a person who represents a child in court in such a dispute (usually a mother) is obliged to prove: 1) financial and material possibilities of a father (not a remuneration which is actually received by a father, but rather possibilities of particular job or remuneration he could receive according to his professional experience and education), 2) reasonable/justified needs of a child (for example costs of education, food, clothing, medical care, interests, sport etc). The basic rule is that you cannot demand as a support for a child more than financial and material possibilities of a obligee. The duty of support in general includes only a minor child (before 18 years old) unless a child contiunue an education (such as university etc). If you have any particular question, please do not hesitate to contact me by this website or my e-mail address. Adw. Joanna Junker