He's not throwing a party for her (right now) because of the Hitsugaya situation (would be kind of mean to throw a party while her Captain is being held prisoner). So Rangiku will get a basket with the following...
A boquet of chrysanthemums and orchids, a small personal
rum cherry cake and a note:
"I know the past few days have been rough--not the best time to celebrate a birthday. But I wish you a good one none-the-less.
Happy Birthday, Rangiku-san.
Come back safe.
- Shuuhei
P.S. Pick any place you want to go and I'll make it happen."