How can this bard best spend her remaining levels?

I’ve been working for months on a character that in my head is a combination of bard and thief. Here’s the basic concept:

Performer. Enchantress. Silver-tongued thief. She’s easy to get along with and a fine negotiator and investigator, but she’s rash, impulsive, terrible with money, and loves jewelry. She’s prone to tantrums and slightly vain. She’s outgoing, unafraid of showing some skin, pretty much refusing to wear anything that doesn’t expose her midriff. Her patron is Sune.

Out of combat, she’s the party face, gathering information and thieving. In combat she casts enchantment spells, illusion spells, and information gathering spells that help the party fight better. If she must herself fight, she’ll use her whip, but she’d would rather run away or negotiate.

I intend to have her take at levels 11 through 20 the prestige class heartwarder (Faiths and Pantheons 196-7). What I need help with are the other levels. I want 7 levels of bard to meet the prestige class’s requirements, but what remaining 3 levels help with the thief part of the concept while still having the character as Charisma-dependent as possible?

Based on the character’s concept, what is are the best class choices for this character before at level 11 she enters heartwarder?