Is it permissible to withdraw usurious interest deposited in banks in Egypt from another fund in Kuwait, on condition that this fund be replenished upon returning to Egypt? And is Zakat obligatory on money that reached the nisab and a full year passed over it, and then another fund was added to it over which a full year has not yet passed?

Sincere repentance is obligatory for depositing money in an interest-based bank. The money must be withdrawn immediately, even through an agent, and deposited in an Islamic bank. The usurious interest should be given as charity to the poor and needy, or spent on the welfare of Muslims. There is no harm in disbursing this interest from what you possess to purify the money.

As for zakat (definition), it is obligatory on the principal amount saved if it reaches the nisab (definition) (equivalent to 595 grams of silver or 85 grams of gold) and a full Hijri year has passed over it. For example, 11,000 pounds reaches the nisab, and its zakat becomes due upon the completion of a year, by giving out a quarter of a tenth (275 pounds). As for the 20,000 pounds on which a year has not passed, its zakat is not obligatory until a year has passed over it. It is permissible to pay zakat on all the money at once when the principal amount's year is complete.