I have an amount of money in a western bank. Usually, I cut my 2.5 percentage Zakaat from the total amount. I have been doing so for a long time before I knew now that the interest is forbidden. Please explain my situation. Furthermore, I spent some money mixed with interest on my family, bought a house, and went to ‘Umrah before I knew that interest is forbidden. Now, I take it out of my account.
Please tell me what I should do now.

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

It is not lawful for you to deposit your money in Riba (interest and/or usury) banks no matter where they are, except in dire necessity. This necessity can be summarized in the fear of losing your money or its being stolen, and the absence of an Islamic alternative (Islamic bank or a trustworthy party that can keep your money safe for you). This ruling is because the Riba banks use the deposited amounts in Riba dealings. So depositing your money in such banks is a help to them which Allah has forbidden.

Allah Says (what means): {…but do not help one another in sin and transgression. And fear Allah. Verily, Allah is Severe in punishment.} [Quran 5:2]

But, if you are compelled to deposit your money there, you should deposit it in a current account and not in a saving account.

In fact, the saving (deposit) account is the result of a Riba contract.

As for what you had spent on family expenditures, building your house and the like, then it is lawful for you since you did not know that bank interests are forbidden.

Allah Says (what means): {But Allah has permitted trade and has forbidden interest. So whoever has received an admonition from his Lord and desists may have what is past, and his affair rests with Allah. But whoever returns to [dealing in interest or usury] - those are the companions of the Fire; they will abide eternally therein.} [Quran 2:275]

But having known the ruling now, it becomes forbidden for you to benefit from those interests as Allah Says (what means): {O you who have believed, fear Allah and give up what remains [due to you] of interest, if you should be believers.} [Quran 2: 278]

Allah knows best.