I have modified my delta printer to print porcelain clay, I got bored printing plastic and I wanted to make my own and customized coffee or espresso cups, you are welcome to visit my link. [www.gofundme.com]
It seems to me that instead of "enhance my homemade printer or buy another one", or a website, or improving your cup design, what you need is a kiln.
Find somewhere (a school, pottery club, art society, whatever) that will let you fire one of your cups. Your project would be much more impressive if you have a final product for people to see.
If you haven't fired porcelain before, I think you're still a long way away from selling cups.
Whilst I'm not averse to giving charitable donations, and I acknowledge that you've done a great deal of work and spent a lot of money, I'll never donate to someone who wants my money to make money for themselves, nor to support someone's hobby/pastime.
If you are serious about this, why don't you make money by selling espresso rocket cups in advance?