Well said Sannah.
I myself am Christian, and I go to church as regularly as my college and work schedule will allow. While I do think that God is able to solve any problem under His watch, for sure, I don't think that the responses you got are appropriate. The problem, in my opinion, is that people tend to forget that God uses His followers, the very same people telling you to "go pray," to do His work. :/ If you see someone suffering as a Christian (or really, as a decent human being...Christianity has nothing to do with humanity in cases like that), you help them...that is the right thing to do. :/
I certainly understand a dislike of the church as an organized institution...indeed, I see quite a bit of hypocrisy myself, and I understand and respect your viewpoint. I'm only sorry that people "of faith" have consistently let you down so.
As far as your friend who got offended, I don't think you need to recant your position, per se. I think if she understood the circumstances a little better, she'd understand. From her perspective, she's likely viewing this as a random outburst, I would think, or otherwise doesn't understand what a well-meaning-yet-lazy/callous "go pray" means to you. I think if she understood your angle and why you made your post, she'd understand.

That doesn't mean disclosing the abuse, nor does it mean that you have to swallow back down what you're feeling, nor making it a public matter. I'd simply PM her, tell her why you did as you did, and that you value her friendship.

That's me, at any rate.
I do hope I was of some help.

Take care, and I hope things work out.
Hugs,
Harley