Hello!

Early in game there is possibility to get potion that allows to respec your champion. I saved it for later but as i was progressing the game [after prison] i noticed that i dont have it anymore. Will i be able to get another one later in game?

I had 8 of these potions by the start of the main storyline, which is after the prison. I think they are somewhat random, but you can get a few from Quest rewards. Also if you didn't use it, check the chests where you get your equipment back in the prison, all your items should be in those couple of chests.