As the reality dawns on the Catholic world that hymns are a substitute for propers--yes, it is very, very sad that this is a point that has to dawn on the Catholic world (!!!)--the first step toward clarity is to start singing the propers in English.
Making this post as short as possible, let me say first that there are three resources that are most accessible:
1. The Anglican Use Gradual. It's free. Download it to your harddrive. I find these beautiful and very useful, almost infallibly so. Their simple structure might deceive you into thinking that they are tedious and something. Not so. They work very well. This is my own personal opinion, and I have dear friends who don't entirely agree with me, and that's fine. But on this I will hold my ground. These are great for parish use, again IMHO. Also the title of the collection is misleading. Most Catholics don't even know what the "Anglican Use" is. In fact it is a third form of the Roman Rite of Mass approved in every way, and this follows the ordinary form calender week by week.
2. The American Gradual. It's free. Download it and use it. These follow Gregorian formulae, and are also great. They are more elaborate. I would suggest these as stage two.
3. By Flowing Waters. Again, I know many people who love this book and I have high respect for the author. It's not really my own choice, not that you should have an regard for my own opinion here. Try them and make your own decision. Sadly, this book is not free, but it is low priced. Note that these are seasonal propers, which is something I can't really embrace: in fact, I don't entirely understand what it means to have seasonal propers. But let's just leave that aside. I point to this resource because people I admire and respect like it and use it.
On translations, please don't post in the combox or write me a belligerent email scolding me for recommending material that departs from "approved translations." Please understand this: there are no approved or official translations of the sung propers of the Roman Rite. Why not? It has something to do with a crazy mixed up confusion over spoken vs. sung propers that emerged in 1970, a crazy mixed up issue over translations of the GIRM that still exist in the current translation, and many other oddball historical anomalies that are not worth going into here. For purposes of this post, you just need to know that these translations are all perfectly fine to sing at Mass. Nor, by the way, do I think that some committee should get to work and pound out approved translations: that is a sure path to catastrophe.