Let her know you intend to sell the car. She knows how much that hunk of metal means to you. She'll feel bad if she really loves you and that should open the door to comprimise now that she knows how much you're willing to do for the relationship and how important she is to you.
Something manage-able would be like 1 weekend a month for car stuff.
- or -
start doing things with her more often. take her out. surprise her with a weekend getaway for two at a spa resort. Ter her you love her at some unexpected moment.
