Firstly, have you got your medical? If not, do so now. I had a student who was super-fit, but due to some anomaly which turned out to be nothing, he had to wait several months before being able to go solo, which wasted a lot of time and money.
Secondly, those who take over 70 hours to get their PPL(H) are as likely to have suffered from poor weather as lack of aptitude...and winter is coming along.
Finally, don't you think you're concentrating too much on basic costs? Does the school have a good reputation; do you get on with the instructor; will they be able to fit you in for the hours you seem to have planned to fly - these sorts of things are far more important than the cost per hour.