It really depends. I've seen at least one player hit gold by relying on his duo that would have never made it on his own. But the flip side is that partner can just as well hurt your chances if they continue to under-perform consistently.
The nice thing about a solid duo is that you increase your chances of winning. A bad duo can make things worse.
If you want to truly get better - climb out of bronze solo. If getting out of bronze is hard for you now, trying to make progress in silver is going to be far more painful.
In bronze, I could have my whole team struggle and still pull out wins. In silver and above, people start to actually have some coordination, albeit by the time you're b1 that's basically low silver unless your mmr is low for b1.