"We've actually been out a couple of times, and every time we leave the house, we hate leaving her, but we have grandmas," the former Full House star, 26, told PEOPLE at the opening of the new Shizue boutique in Beverly Hills.
"They wrestle us for them, anyway!" said Herpin about the couple's mothers.
"His mom won tonight, my mom had her a couple of nights ago," said Sweetin. "It's really amazing. We have the best babysitters in the world."
Having revealed, in a PEOPLE cover story earlier this month, her struggle to beat an addiction to crystal meth and turn her life around and become a responsible mother, the actress (who from age 5 to 13 played middle child Stephanie on Full House) said the reaction to the article has been positive.
"I've had so many people come up and really just thank you for sharing my story. They give me the most amazing well wishes for the new baby," says Sweetin. "I was really happy that it came out and that we were able to turn it into something good."
Best of all is baby Zoie. "Everybody is so excited to meet her," Sweetin says of her former Full House castmates. "They're like, 'We can't wait!' They're going to meet the new little addition to the extended Full House family very soon.
Help with Weight LossAs for losing her pregnancy weight – which just doesn't seem to disappear on its own – Sweetin says, "I'm still working very hard and dressing strategically. I'm doing NutriSystem, and they have been phenomenal. I'm working with them."
Herpin, 31, has also joined the diet program. "He's lost, like, 35 pounds, I've lost 15 so far. I want another 10 pounds, but it's so hard, especially being in this business – you feel like you have to look like you've never had a child, like the next day."
A trainer is also onboard "twice a week, and then I try to fit in another day, but it's touch and go. [I say] I'm going to work out now, [but] the baby needs to be feed, [so], okay, I'll sit and watch TV for a little while [instead]."
Besides her and Herpin's pitching a reality show "about new family, just about the new baby," Sweetin says, "I'm shooting a movie at the end of August, beginning of September."
She also speaks "at different universities all over the country about my experience with going to rehab and all that, so just like our life basically, and it's really full of amazing, wonderful things right now."