Adding extra button to media uploader

Hey, I am creating a custom post type for my companies new website, and in order to provide the best user experience I need to add another button (or a few) onto the media uploader which will insert the SRCs of selected images into input fields on the page.

Unfortunately, I have no idea where to add these buttons, and there seems to be very little information on the new media uploader. From what I can gather, it appears the majority of the uploader is generated purely with JS, so how would I go about adding an extra button next to “Insert Into Post”?

Thanks in advance.
Robin