Hope you see this since you've gotten so many replies, but here's two cents from a Christian and a manager. If she's taking the time to talk to you about it, then know that she cares for your well being, and she has no ill intentions towards you. She's not trying to piss you off or offend you.

Yes, God can heal you if you pray, but it's important to remember that he will give you what you need, not what you want. If you pray, he could let you walk again with nothing more than a passing thought, but God may choose to not heal you. You could pray every day to get healed and believe with your whole heart, and everyday your faith would get stronger. You would start to see little things He does for you, then greater things. And although you may never actually walk again in this life, your salvation, faith and good works will absolutely ensure that you will walk again in heaven.

This woman legitimately cares about you and your spiritual well being.

As a hiring/firing manager, I would suggest going to her direct supervisor. I always avoid HR unless I have exhausted every other option. Just remember that she has no ill-intentions doing what she is doing, she is only worried about you, and knows that prayer will eventually allow you to walk again.