Let's consider what you know: you have the last block, the IV, and the entire ciphertext. What you don't know is the key or the plaintext. Since CBC-mode encryption uses the IV directly only with the first block you must find the first block, before the IV even becomes useful for your attack. Since the CBC mode uses
AES(plaintext[i] XOR ciphertext[i-1], key) and you know the plaintext of the last block, as well as the ciphertext of the previous block you end up with a generic known-plaintext case. So what can you do?
Knowing the IV won't help since the IV only applies to the first block.
AES(something XOR iv, key) = ciphertext but since you don't know the plaintext or the key it might as well be
AES(something, key) = ciphertext. Knowing what (something) is won't help either since you'll simply end up with another known-plaintext scenario, so even if you got the first block of plaintext as well the key is unobtainable - that's the point of encryption, and a padding oracle is an issue with the mode of operation, not the algorithm itself.
I'm sorry to say, you're SOL.