Most Anesthesia schools require the GRE. Look into other programs and you will see this is a requirement across the board and that UT was an outlier for not requiring it. Also look into the ACLS/PALS/BLS requirement as that is a standard also. You may as well get your CCRN while you are at it. The reality is that being a CRNA is not just about the job, but about the group that you are about to enter. CRNA's have the highest percent of non-required members in the AANA (94%) and these members are involved in what happens in the profession. You are not just going to school to get a 'job', you are going to enter a profession.
The requirement for the GRE is new this year. It was not there last year.
As for preparation, get one of those verbal flip page study aides and take it with you every where and study it. I raised my score 110 points just doing that. Also, take a college algebra and you will also raise the math score at least 70 points. I don't think you have enough time for it. If you are serious about school, hit the floor running on this, otherwise you might be waiting another year to re-apply and may not get in. The competition is going to get worse for you the longer you wait.
The CCRN part was an added bonus. My previous employer did not require this, so I did it on my own as it was something I felt all ICU nurses should have. If you already have this, then know why it is important! There was a study that the AACN published in one of their magazines that compared patient outcomes of CCRN... really had changed my mind about why I wanted to do that. Again, you may not have enough time to do this before the deadline. It is August though, and I got my paperwork in at the last minute and still got in.
The point is, do and be all that you think you should be to get into the profession. Then add some to it. Everyone is different that is accepted and has a different story to tell, but they are all top notch