Dear 1234,
the first reply says it all. Nevertheless, I'd like to comment a couple of points.
1. An audition is about standing out the crowd. Two things to consider:
a. you must have a solid performance of whatever you play, and here you must face that you don't have "still one year" but you do have "only one year". Preparation for some auditions usually takes two or even more years, but I'm not saying you must not enter. Do it, but know you have just the right time to perfect a new work that is right on your current possibilities. A step above and you will regret.
b. you are not playing for yourself, but for a jury that has been listening to all sort of auditions in the last decade, sometimes the last half of century. So, all the stress on "don't go with the pathetique, etc" is not enough. Don't even think about playing that. Schubert is a remarkable good idea. The same applies to the study: there is a vast literature of virtuosic studies. Chopin is the most conservative and overplayed choice possible.
2. Choose as many pieces you already play as possible. You have five points, and as far I did understand you have only two prepared works (Bach and Liszt). So, you must play from scratch a complete Classical sonata, a 20th/21st piece, and an etude. It feels like an impossible task, but let's assume you don't have any options. If that is the situation, don't go with another sonata or large work for the 20th century. Pick up a single piece from 5 to 8 minutes long, and call it a day.
3. About the 20th century sonata, although BBS have an important advice (write to the institution), it is the most usual to prefer complete works. Some institutions are clearly against fragments: you simply can not play a work that is not complete, and it is write down somewhere. However, another institutions say nothing, but your jury will most likely kill yourself if you go with a single movement. So, a word of caution: never play incomplete works in such a situation. If you don't have the time to prepare a complete sonata, theme and variations, etc, do the simplest possible thing: choose a single movement work.
Best regards, and very good luck!
Jay.