Help get specific address private key I want to know if someone can help me with this situation:
Two years ago I changed the password of my Bitcoin-Core wallet and forgot it.

I sent my wallet.dat to some person, who claimed that will crack it down and return my coins with some fee.

In the wallet there were only 2 addresses, and after some time the coins dissapeared, but only from one of them. I saw in the blockchain that they were "mixed" or split, in a way not to be traced.

Here is the address they went to: https://www.blockchain.com/btc/address/1PFygtEEhi4spjHJ3DHEBvgVpNp8oBY4A2 

Coins from the other address are still in the wallet, and I found my password for the core wallet, but I don't know how to use it for that specific address with the coins left.

There are 1.3 BTC inside / still 8.30 stolen / but it will be a little relief for me if I can get them.

I have my original wallet.dat file also - so if anyone can help me, I will be very grateful.
It isn't clear why your "helper" would have missed 1.3 BTC at a separate address in the same Bitcoin-core wallet. Did you use the "Account" feature that was recently removed from Bitcoin-core?

I would do the following

Prepare a new empty wallet using your choice of hardware wallets or software wallets (1). Make a careful note of the seed-phrase/recovery-phrase or private-keys. Practice restoring this wallet from only that noted secret information.

Download and install the latest Bitcoin-core onto a clean PC and reinstate the old wallet.dat file into it (2), then use the newly found password to open it 

Let it synchronise (may take days or weeks)

Immediately any money is visible, transfer any money into the other wallet.

If no money is visible, try to find out the status, in the wallet, of the address you say holds 1.3 BTC. Note that the command line interface(3) may be helpful in listing addresses the wallet is keeping track of.



References


https://bitcoin.org/en/choose-your-wallet
Import wallet.dat into a new Bitcoin-Qt client
https://en.bitcoin.it/wiki/Original_Bitcoin_client/API_calls_list