All the other postdocs have almos no publications and have been around for 6 years average.
This statement is telling you something! It's telling you that this lab has a high chance of being a career killer. Six years as a post-doc will most likely close off any possibility of getting into industry, and the lack of papers is going to be a major impediment to an academic opportunity. This alone should tell you what you should be do.
It sounds like you live somewhere where there are multiple opportunities to work in your field, which should make your choice easier. Don't worry too much about continuing in "the same topic", though. While it's familiar and therefore comfortable, it's not the only interesting project out there. Being adaptable is only going to help your career.
Also, what are you going to do when you finally decide to seek a "real" job? If you're going to insist on staying in the same location you're going to severely limit your opportunities and extend the time you spend searching. (Remember that a post-doc's only objective is to get out of that post-doc into a permanent position.)
Don't get too "hung up" on your publication record. Focus on what you have
accomplished and how it demonstrates your productivity. You can mention how small your PhD lab was, but don't use it as an excuse! (Think "Even though we only had [xyz] I was able to do [abc]," instead of "I could only do [abc] because we were so small.")