If her name is on the title you most likely can't force her to sign over the title unless you had a contract that indicated what would be done with the car if you broke up. This is exactly why I recommend everything be in writing when you co-mingle property without marriage.
Attorney Chris Beck
Beck Law Office, L.L.C.
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If you can prove that you paid for it, then I'd think about suing her in small claims court under a theory of unjust enrichment.
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