I can PM you my e-mail and you can send me pictures of her, if you want to. I can either post them here, or just look at them, and tell you what I think.
From what you're saying, it does sound like she is underconditioned.
For a cow that milked 3 gallons a day, she must have been way underfed or possibly has some disease that caused her to lose weight.
If she was mine I would test her for all the major cow diseases, and take it from there.
If she is disease
free, it really should not be hard at all to put weight back on her at this low production, or if dry.
You didn't say if she has good heats? If yes, I would breed her now and not worry about her weight. She would have 9 months to get in top condition.
If she doesn't cycle (no detectable heats), then you would need to bring her back in shape before trying to breed her.