Try
http://www.memoriesbybetsy.com/Memories_by_Betsy/Welcome.html . She does some really cute things and is wayyyy cheaper than disney florist. You can choose from any number of themes. When my son celebrated his birthday he got a basket with a pirate theme. I told her what I wanted and she went shopping at WDW. She is wonderful to work with. The basket she puts the gifts in are disposable, but that is okay with me. Less stuff to drag home! They were at the desk upon check in. You can either have them delivered to your room after you check in, or you can pick it up right then.
Also, have your resort send up balloons and a card from her favorite character (some aren't available). My boys both got Mickey. This is free! The only resort that can't do this is AKL, due to the balloons posing a safety hazard to the animals outside.
Make sure she wears a birthday pin everyday during your trip and note her birthday on both your hotel ressie and ADRs. You may already know that they will bring her a special dessert or cupcake if they are aware it is her special day.
What about a quick stop at the mainstreet barber shop for a little "pixie dust" in her hair? Quicker and cheaper than BBB.
Of course, breakfast at Chef Mickeys might be great since she loves Minnie. And make sure she gets to visit Pixie Hollow to see Tink!
If they have birthday balloons in the park, buy her one and tie it to the stroller.
Maybe buy her the My girl disney doll with either the minnie dress or the tinkerbell dress. A little pricey, but cute!
Stop at one of the bakeries and get her a cake. The Mickey head ones are cute. I think the Main st. bakery has them and the one on the Boardwalk.
If I think of anything else, I'll let you know!
BTW, where are you staying?