If you want a Baptist church, have a look at the Baptist Union of the Czech Republic for some general information. There is also the International Baptist Church of Prague. Even if this is not what you´re looking for, that´s no reason to stop you putting your head round the door. Their website states they also welcome, “agnostics, unbelievers, seekers, the curious, sinners, doubters, strugglers, the spiritually wounded, the lonely, the broken hearted, the disillusioned.” That seems to cover just about everybody.