You could go down to the police station and see what they can do for you..or you could call them.

if you can e-mail her,do so, request a time to pick up your things. if you can't, write, and send by Certificate of Mailing ( you can ALSO send request by Certified mail, not the same) or go over with a small friend, if you need help picking up the stuff let them stay in the car until the storage is open. if she is there you can call the police and tell them she is withholding your property, don't be angry.

written proof that you attempted to retrieve your things is important, if you can't get it a witness is still good. if you have a witness or something in writing, file in small claims. if you owe rent she still may not withhold your property.