As I wrote in my initial comment it could be that you have to go back to your home country in order to apply for a visa. With said visa you can come back to Germany to apply for a residence permit (which you are entitled to get because you are married to a German citizen). I know that sounds like a totally pointless rule, but unfortunately it’s not uncommon. I can’t tell you though if that’s what Ausländerbehörde had in mind when they send you the letter that you mentioned. To make a definite statement about that I’d need to have more information about your situation.
Germany (as well as the whole European Union) try to make sure that the asylum system is not misused by people to enter the labour market. That’s why having a job and paying taxes is not directly linked to the asylum procedure and authorities’ decision to grant a residence permit. Of course there is different laws in other countries. That’s why your sisters can live with their husbands in peace in your home country. But in Germany there is different rules :/