Yes, you can file an injunction against her to stop her use of the trade secret protected information in your computer system, which includes customer and client lists.
You can also sue her for the theft of the trade secrets, including statutory damages for the loss caused to you and the unjust enrichemnt (money that she made through the theft) from her.
You should hire an intellectual property/ employment law attorney to file suit against your former employer.
Some good starting points are:www.lawyers.comwww.avvo.comwww.martindale.com
I suggest that you try to get an attorney to represent you on a contingency basis, so you would not have to pay the attorney unless you receive a settlement or a verdict in your favor.
Unfortunately, it could be difficult getting an attorney interested on a contingency basis, depending on the finances and resources of your ex-employee, since many attorneys will be less interested in suing clients when they cannot receive a substantial judgment against them (and actually collect it).
Also, prior to retaining an attorney to file an injunction on your behalf, you could also send a 'cease and desist' letter informing her to stop her illegal contact of clients from your client list.
You could threaten her with criminal contact, since trade secret theft is illegal under United States law, although it'd be unlikely that they would pursue a prosecution against your employee in this case. (Trade secret theft criminal cases normally deal with the theft of proprietary information that is worth (at least) millions of dollars).
For reference about the cause of action see California Civil Code Section 3426 to 3426.11, available here:http://www.leginfo.ca.gov/cgi-bin/displaycode?section=civ&group=03001-04000&file=3426-3426.11