you normally can't make an already installed Q2A site integrate to another platform. because Q2A has already users and content related to them.
however a good programmer will be able to write an script to help you with this. First you need to have a clean integration with your platform, then script should import users and their related content(posts, votes, favorites, ...) from old Q2A installation to the integrated Q2A section while it searchs and handles duplicate users.