Your subsequent post is different than your original... and that difference is substantial!!
Original: "It is my name on the car registration not hers."
Now: "It says both our names on the registration but has my address."
That is a MAJOR difference.
So, with that 'new' fact.... both of you have equal legal title to the vehicle (address doesn't matter). Accordingly, for some reason, the co-owner decided that she was entitled to take possession of the vehicle (which is within her rights). And until such time as the title is transferred (with both of your signatures), both names will remain on the title.
Lets take a look at your new questions:
Q1) "They told me since she is the co-signer she is 100% responsible for the loan, and for me it doesnt matter."
A1) I don't know who the 'they' is, but 'they' are not correct. Both of you are equally responsible for the debt. Most co-signer agreements list a primary and a secondary liable party. The primary would normally make the payments.... and in the event of breach, the secondary would then be liable for the payments. And any credit history for one.... will be reported for both. That is why it is so important to NEVER co-sign for someone else. It is just like giving them a credit card with your name on it.
Q2) "So can I just take my name off it then since obviously she is responsible and if i dont pay it will relfect her credit."
A2) Nope. Both of you are equal owners. As noted above, the only way to get your name off is for a mutual title transfer or sale.
Q3) "I would much rather go buy something else and get it in my OWN NAME."
A3) You may get that opportunity anyway.... and then own 1 1/2 cars!
Q4) "Or can i call the police and say she stole my car, since my name is also on the registration and its my address."
A4) Nope. You are BOTH owners, so there was no 'theft'.
Your only available option as I see it is to try to negotiate some 'sale' of the car to remove your name from the title. Simply, you can offer to sell your 1/2 to her for a minimal amount and, if she accepts, get payment and sign the title. Or, you can take her to court to try to recover your payments.