Listen mate im gonna be real with you: If you are not willing to market your book, then you wont see much if any money for it.
You don't have to pay for ads, but you do have to network.
Put the book on your twitter, your facebook maybe, or other social media platforms. Be an extrovert.
For example, people on Wattpad rely mainly on being sociable to gain attention. It's all, "Hey i read your story and here my thoughts. Would you be willing to read mine, too?" And so on and so forth.
It's not hard work to spread word of your story, but it is tedious.
Post your book at multiple websites and make It clear you're in need of money and that the story will be continued with that in mind. You have to be upfront with your readers, and if they have the means to support you and like your story they will likely be willing to help. Just dont beg for it in every chapter and you should be fine. Leave notice of your intention in the synopsis, make it short and sweet and that should be enough.
Also, don't market your book towards teens. Market it towards young adults. Teens usually don't got a job, which means no money. Appeal to the right audience with your story going forward. Since you have a patreon, keep a reserve of chapters so you arent pressed for time and can release chapters periodically at your leisure. Note that with patreon, you dont have to solely write content for your story. You can even write short stories, one-shots...some people make "what if" chapters based on their stories, and others make smut. Simply put, you can make other kind of content that other people may be interested in seeing and paying for. Make separate tiers for these what if chapters or whatever bonus content you make on your patreon.
This is so they will only be paying to see what they want, and also so you dont just bundle everything up and lose out on revenue by giving them more than what they pay you. No smart businessman sells a whole gift basket full of goodies for a dollar, see what I'm saying?.
This is not writing advice, I'll leave that to others. This is just advice on what you should do if the goal is financial aid.