Puls update

I have found the birth record of Katherina Elisebeth Puls. I found it after finding her death record. She and her family went to Jesus' church in Riga. She was born in 1821 and had 6 siblings. Interestingly, her parents married over 7 years AFTER she was born. Obviously, I found their marriage record. That means, of course, that I've found another family name, though this one is FAR less interesting. The name is...BERG. There were a TON of them in that church! Anyway, I would now like to find the death records for either (preferably both) of Katherine's parents, as that may help me find their birth location. I'm still waiting for a city/location outside of Latvia for some blood relative. The best I have thus far is a Sperber whose father was born in Lodz. Maybe there is a Lotz in Latvia, but I know there is one in Poland and is a reasonably major city, so I am just going to assume he is from there. Regardless, I will not be pursuing that family line any further.