If you can cook, make her dinner instead of taking her out. She'll appreciate it even more! Light candles, play some soft music, dance with her, have some flowers (in her favorite color if you know what that is - doesn't have to be a room full), and get/make her a cd of music she likes or something equally personal but not overdoing it. Good luck! You don't have to spend a bunch of money to touch her heart and give her a really wonderful and memorable birthday.