I forgot my new password in bitcoin core, but i remember old password and i have old version of wallet.dat (with old password).
If i just replace it will it help me to take control and not loose today balance?
I am not sure and afraid of this step. Need advise!
Yes sure, just replace your wallet.dat while your bitcoincore-qt is NOT running.
Backup you newest wallet.dat as well.
You will get access to the address you had in your old wallet, if you imported new addresses in the meantime that will not be recovered using your backup.