Soo many people,so many problems,Trust in Allah then there will be no problems at all.
Wish it was so easy Sameenji! ALLAH brings problems to the people he loves and trusts!
You seem like a lovely person "Marriedsingle" and I respect you for trying to make it work.
I think from experience within friends and family, please do not spend too much time thinking things will change.
You will know enough of her nature by now to know that yes she may improve but maybe an improvement of 10% either way.
The only way that she will change more than that is through some form of shock which isn't the way I'd wish her to learn.
Beleive in ALLAH, do the best you can and whatever happens remember you did your best and whatever happens it is all for the best!