If two tenants sign a 1 year rental agreement and 1 decides to move out are they still responsible for half of the rent?

I signed a 1 year lease for an apartment with my girlfriend at the time, two months into the lease she moved out unannounced, but is still on the lease. This has created a problem, because I only signed on understanding that I would only be responsible for my half of the rent due for the 1 year term. I understand that she would still be liable for any property damage, and liable for eviction, and collection of past due rents if I were to become delinquent on payment. Many of her belongings still remain in the apartment. I feel I am injured, because I would incur extra hardship and costs to relocate to less desirable living quarters. Am I entitled to make her to continue to pay her half, or ask her to buy out her remaining portion of rent due until the end of the lease term?