MailPoet: Plugin Customization for selecting Posts into Newsletter

We need to customize the plugin so client can use the "Post" function to add/remove posts into the Newsletter. Currently client needs to add posts to the newsletter manually, which takes too much time for client. Client should be able to just select Posts from the list which should be added in the Newsletter. Budget is not high for this unfortunately. If you are willing to meet us in the middle, we will be able to give you more WordPress projects with higher pay.