It's very unlikely that you can become pregnant because of how long she has been on hormones. It's likely that ship has sailed. If she were to get off of hormones, she may have a chance of becoming fertile again, but that is very unlikely. I'm assuming she has also been on an anti androgen as well. To be honest, if you are hoping to have a biological child, it's going to be pretty difficult.
Having said that, there are many ways for you to have children. If she stored sperm, then you could go the insemination route. Also, adoption is a wonderful option and there are so many children out there in need of a loving home.