It is a bit confusing how you use the word "points". You first say you get points by asking questions (as the standard points system does), but then you speak about points for activity, which is something that doesn't exist.
I understand the activity issue you talk about. It is just not part of Q2A. You'll have to code that logic.
However, I don't understand if you would like that activity to increase the standard point system or if you just want to use some other custom point mechanism that gives X tokens per question view and, when those tokens get to 500, those users will be allowed to access the poll.