Many graduates work for a year or so after college before applying to a graduate program. Getting out of the classroom into the "real" world is a good way to test your interests and abilities and to make long range plans.
The delay should not hurt your chances for admission, in fact, it may help if your experience is relevant to your plans for graduate study. The extra year can help you decide on a focus for your studies. Use the application cover letter to show how the extra year has heightened your academic enthusiasm and increased your stability.
Your interests may change as you work in your job after graduation. There are programs to consider besides psychology. For example, a business (M.B.A.) program takes two years and attracts many students with applied or practical interests. Psychology majors going for a M.B.A. do best specializing in Marketing, Management, or Personnel programs. Some students apply for medical school, law school, or go for a completely different academic program like sociology or American studies.
If you take the GRE's in the fall of your senior year, you can change your mind and delay applying to graduate school. You may take the GRE again later, and the GRE office will report both scores. If you do better the second time, you can point out in the cover letter how this improvement is further evidence of your interest and determination.
Letters of Recommendation
One letter should be from your work or volunteer supervisor. This letter would cover your recent activities and deal with your performance in a non-academic environment.
When asking former teachers for a letter, call (or, if you can, visit) them to refresh their memories of you. Give them a revised summary sheet covering both your college activities and what you have done since graduation. Describe your current career plans and explain why you chose to apply to certain particular schools. You want these letters to show that the writers know of your current plans and goals.