The rule is you must have 6 months or longer left on your permanent resident card to apply for citizenship without renewing your PR card. I would definitely file I-90 to replace the PR card; when you go for fingerprinting do an INFOPASS to also get a passport stamp as evidence of your PR status for work. I would recommend you also file for citizenship (N-400) unless there is a reason you would not be eligible..
Lynne R. Feldman, Attorney at Law
Concentrating in Immigration Law
Maybe, just for the sake of an argument, there is a third way - consult with an experienced immigration attorney so you would not feel insecure about what to do and would not need to post requests for free legal advice on a forum where it is only appropriate to ask for general information.
NYC EXPERIENCED IMMIGRATION ATTORNEYS www.myattorneyusa.com; email: email@example.com; Phone: (866) 456-8654; Fax: 212-964-0440; Cell: 212-202-0325. The information contained in this answer is provided for informational purposes only, and should not be construed as legal advice on any subject matter.