What should I do with the money I took after swearing not to take it? And is it permissible to give it away as charity?

If an oath is taken to abandon an obligation or commit a forbidden act, then it is obligatory to break that oath. Obedience to parents is obligatory within its Sharia-compliant frameworks. Therefore, you must take the money your mother gave you, and you owe expiation for your oath, as stipulated in Surat Al-Ma'idah: feeding ten needy persons, or clothing them, or emancipating a slave. But whoever cannot find [the means] - then a fast of three days.