Are there any restrictions on applying to the same graduate school in two consecutive years?
A solid GPA and letters of recommendation is nothing to sneeze at—particularly if one of the people who wrote your letter of recommendation is a co-author on the publication.

You don't need to publish the paper on arXiv if you and your co-authors don't feel it is appropriate; however, you can mention that you have a manuscript available, and submit it along with your application (if the department to which you're applying permits it!).

However, I wouldn't wait an extra year just to "improve your odds." Apply this year—if you don't like the results, try again next year.