Let's hope Nick Lachey is ready to change diapers: Girlfriend Vanessa Minnillo tells PEOPLE she's looking forward to mommyhood.

"I can't wait to be a mother one day," the TRL host, 26, told PEOPLE at the Bacardi Limon Express Your Style Design Competition Thursday night in Manhattan.

"I want to bring three boys up to be good men in this world and then one little girl. I always say I want three boys and a girl but at the end of the day I just want healthy kids."

Looking flirty in a figure-hugging Nanette Lepore sleeveless dress and gold lamé Hollywould shoes, Minnillo, who has been dating Lachey for almost a year now, said her beau "is a nice guy. He's in the studio recording right now [in] L.A., Nashville, New York. All over, with something for everyone to look out for."

What is it about them that clicks? "I think the thing that makes it work is our privacy," she said.

Minnillo helped pick the night's winning design: a pale yellow chiffon 'Retro Cocktail Dress' designed by Patricia Samaniego. "Her inspiration was Vegas," said Minnillo. "One of the sexiest things on a woman's body is her back and her shoulders. I tend to slouch and I'm not always standing upright and sucking it in.

"That's why I love her dress. It is very flowy and comfortable in the front and the back is exposed. The legs are open and exposed. And there is this beautiful chiffon material – very flowy, very fun, very Vegas, very Bacardi."

Minnillo spent the afternoon watching the five designer finalists cut and sew their creations. So does she sew at all? "I picked up knitting two winters ago and that lasted all of four rows of the scarf. Just because to me it wasn't relaxing, because I'm OCD – obsessive compulsive – and the hoops are supposed to be in perfect and it was driving me bananas how one side was looser and one side was tighter