As regards La Nuova: it is known in English as Vita Nuova. I had a look at the online catalogue of the British Library,
http://blpc.bl.uk, and a number of English translations are listed. You could write down some of these and see if a good bookshop either stocks them or can order them. If they cannot, your local library may be able to arrange an interlibrary loan from any library, even the British Library, but I believe they can take a long time to arrive. If by any chance you are a part time student, and your university's library does not have the book you want, there is a scheme (London Plus I think) which allows you to visit and borrow from up to two other university libraries. Good luck.