You can have a deed prepared for $100 or less or just do one yourself in this situation. I'm not sure exactly what recording fees are but it's in the neighborhood of $30 I think, I'm sure someone who bought recently resale will know. You don't have to have the full closing again and that's the price they were quoting you.
DVC will waive the ROFR for this situation since it involved a primary relative and just adding your name to her name, you need to contact Member Administration to get the details. Prodox will do a whole closing thing including escrow and recording for $200 but you must take care of the ROFR portion at that price, they add $100 more to do that.
$300 is ludicrious, when I had this problem, I think DVC wanted $100 to fix it and they didn't do the original closing. My first contract did not include my wife and the lawyer wouldn't fix it unless I paid the recording fees a second time. I refused, it wasn't that big of a deal to have me pay for a service twice that should have been done right the first time. I really should have reported Jerome Tepps, PA out of Ft. Lauderdale to the Bar for that as I had intended.
We added my wife as an associate member and we thought and were led to believe that would give her a card but alas, it did not. Well, when I bought a second contract, my wife made sure she was on it. Guess what, we got new card for both of us with the new contract number then when it came time to get the new cards for the old contract, they sent her one as well for that one.
While I understand your predicament, technically the member must be present and doing the purchasing to get the discount. I'm sure though they'd never look if you had her card. In your situation, I'd get the deed changed but do it on the cheap.