I’m under a lot of stress at work because my manager keeps confronting me about a director I went to HR about almost a year ago – she was a very difficult person to work for and was very unethical at times – because I brought it to HR’s attention, she lost some of her power – my current manager was able to benefit from me doing this by becoming our new manager – but the thing is that I still have to work for this director indirectly and find that my manager takes her side when making desicions – my life is a living hell for the last year at work because it feels like I don’t have anyone on my side and I don’t know what to do – what would do???

Going over someone’s head is dangerous and should be a last resort. I was once told to use the 48 hour rule — discuss the situation in a non-threatening way with your manager (making it clear that a change is needed), and if nothing is done to fix the situation in 48 hours, then go over up one level. Keep doing that until it is resolved.
You may or may not have done that, but that is water over the dam…
You may not like confrontation, but you need to go to your current manager to discuss this, asking for advice on how to better work with the old director. If the manager is any good and wants to keep you, he’ll do something.
If the company is larger, go back to the HR person and see if there is another department in the company that would be a better fit. Be aware that this could come back in the future if you and the old director are still there in 5+ years and you’ve risen to the point where you will work together again.
It is best to have a discussion face to face. Sometimes it helps to have the discussion outside of the office at lunch or after work to get on neutral social ground.