Sunshine, we all make mistakes... and all we can hope to do is try to make up for them (isn't that why we are all here, trying to make up for mistakes that happened in our Rs?)
I don't think it was selfish, and I applaud you for having the mechanic put it back in the car.
As far as moving out... start gathering information about your own place, but don't rush into anything. Give her some time/space while you create your plan B... maybe she'll calm down and get nervous when she sees you taking steps for moving out and she could 'take it back', but even if she doesn't, you'll have your next steps ready.
I'm really sorry this happened to you. I can tell how bad you feel about your mistake.
(((hugs!)))
M-31, H-31 T-9, M-7 S-6, s-20mth sep 8/1/11 ILYNILWY 11/29/11 Creating separation papers. Discover H has feelings for BFF, she does too 1/11/12 H moves out 1.20.12